DAMASCUS, Syria — The sound of artillery reverberated Thursday through a predominantly Christian village north of Damascus as government troops and al-Qaida-linked rebels battled for control of the mountainside sanctuary.

The hit-and-run attacks on the ancient village of Maaloula, one of the few places in the world where residents still speak Aramaic, highlighted fears among Syria's religious minorities about the growing role of extremists among those fighting in the civil war to topple President Bashar Assad's regime.

The fighting came as President Barack Obama's administration pressed the U.S. Congress for its authorization of a military strike against the Assad regime, while the president arrived at a G-20 summit in Russia expected to be overshadowed by Syria.

The fighting in Maaloula, a scenic village of about 3,300 perched high in the mountains, began early Wednesday when militants from Jabhat al-Nusra stormed in after a suicide bomber struck an army checkpoint guarding the entrance.

The group – listed as a terrorist organization by the U.S. State Department – is one of the most effective fighting forces among Syrian rebels. The suicide attack triggered battles that terrorized residents in the village, famous for two of the oldest surviving monasteries in Syria – Mar Sarkis and Mar Takla.

Online video showed rebels in the streets, some firing truck-mounted heavy machine guns in the direction of the surrounding mountains. The video appeared authentic and matched Associated Press reporting on the fighting.

Residents said Wednesday the rebels took over the mountaintop Safir hotel and were firing in the direction of the community below.

Rami Abdul-Rahman, director of the Britain-based Syrian Observatory for Human Rights, said that despite a heavy army presence in the village, the rebels staged hit-and-run attacks, at one point patrolling the streets on foot and in vehicles, and briefly surrounding a church and a mosque before leaving early Thursday.

Heavy fighting around the village, which is on a UNESCO list of tentative world heritage sites – continued throughout the day, and heavy artillery echoed in the village.

"The stones are shaking," said a nun at the Mar Takla monastery. "We don't know if the rebels have left or not, nobody dares go out."

Frightened residents expected the militants to return to the Safir hotel, she said, adding: "It's their home now."

She spoke with the AP on condition of anonymity for fear of reprisals.

Al-Mayadeen TV, a Lebanese station who has an embed with the Syrian army, broadcast live images from the area Thursday evening that showed smoke rising from behind the hotel, suggesting the military was shelling it.

The nun said about 100 people from the village took refuge in the St. Takla convent that she helps run. The 27 orphans who live there had been taken to nearby caves overnight "so they were not scared," she said.

Maaloula, about 40 miles (60 kilometers) northeast of Damascus, had been firmly under the regime's grip, despite sitting in the middle of rebel-held territory east and north of the capital. The village was a major tourist attraction before the civil war. Some of its residents still speak a version of Aramaic, the language of biblical times believed to have been used by Jesus.

In 2008, Assad and his wife, Asma, visited the St. Takla convent, eating with Christian orphans there. In the same year, Assad took former U.S. President Jimmy Carter for a stroll in the area.

The attack highlights fears among Syrian Christians that the alternative to Assad's regime, made up mostly of Alawites – followers of an offshoot of Shiite Islam – would not tolerate minority religions.

The nun who spoke to AP said there were reports that the militants threatened villagers with death if they did not convert. The report could not be independently confirmed.

Such fears have allowed Assad to retain the support of large sections among Syria's minorities, which includes Christians, Alawites, Druze and ethnic Kurds, throughout the 2 1/2 year civil war. Most of the rebels and their supporters are Sunni Muslims.

Elsewhere Thursday, a car bomb exploded outside a research center belonging to the Ministry of Industry in the area of Soumariya near Damascus, killing four people and wounding several others, a government official said. The official who spoke on condition of anonymity because he was not authorized to talk to reporters.

Three people were wounded when mortar shells hit two residential neighborhoods of Damascus, the state news agency SANA reported.

In the northern province of Aleppo, a Syrian surgeon working for an international aid group was killed. Doctors Without Borders said the 28-year-old surgeon, Muhammad Abyad, died in an attack. Abyad, whose body was found Tuesday, had been working in an Aleppo hospital run by the group.

The conflict started in March 2011 as largely peaceful demonstrations against Assad's rule. It turned into a civil war after opposition supporters took up arms to fight a brutal government crackdown on dissent. Two years of fighting have led to a stalemate, with the rebels controlling much of the countryside in the north, east and south, and the regime holding most urban centers in the west, where the majority of Syrians live.

More than 100,000 people have been killed, with nearly 7 million people uprooted from their homes. U.N. officials estimate that 5 million have been displaced inside the country while another 2 million have fled to neighboring countries. The total amounts to nearly a third of Syria's population, which was 23 million before the fighting began.

U.N. humanitarian chief Valerie Amos met with Syrian government officials in the capital, lobbying for access to civilians trapped in areas where fighting has raged.

After meeting with the president of the Syrian Arab Red Crescent, Amos told the AP that she is "extremely concerned that the situation on the ground is becoming worse."

An alleged chemical attack near Damascus in August has brought the U.S. to the brink of launching punitive airstrikes after the Obama administration concluded that Assad's forces were responsible.

Obama has been lobbying for international and domestic support for punishing the regime, which the U.S. says fired rockets loaded with the nerve agent sarin on rebel-held areas near Damascus before dawn Aug. 21, killing hundreds of people.

Obama has called chemical weapons use a "red line." Top administration officials have argued before the U.S. Senate and around the world that Assad would take inaction by Washington as a license for further brutality against his people.

So far, however, Obama has won little international backing for action. Among major allies, only France has offered publicly to join the U.S. in a strike.

At the Group of 20 economic summit in St. Petersburg, Obama will confront Syria's closest supporter, Russia, as well as foreign leaders skeptical of his call for an international military intervention in Syria.

Moscow and Washington have sharply disagreed over ways to end the bloodshed, with Russia protecting the Assad regime from punitive actions in the United Nations. The U.S. has backed the opposition and repeatedly has called on Assad to step down. He has refused and the U.S. has been supporting the rebels with non-lethal aid and by training some rebel units in neighboring Jordan.

Russia's Foreign Ministry said Syrian Foreign Minster Walid al-Moallem will travel to Moscow on Monday for a meeting with his Russian counterpart.

European Union President Herman Van Rompuy urged U.N. investigators to release information as soon as possible about the purported chemical weapons attack Aug. 21 so that the international community can decide how to respond.

SANA said Syrian Parliament speaker Jihad Laham sent a letter to the President of the European parliament, Martin Schulz, inviting members to visit Syria to follow up on the outcome of the U.N. investigation and help develop terms of reference for any subsequent investigations.

___

Karam reported from Beirut. Associated Press writers Barbara Surk in Beirut contributed to this report.

Also on HuffPost:

Loading Slideshow...
  • Syrian refugee, Ahmed al Delly, 59, from Daraa in Syria, reacts as he speaks about his wife, four sons, and two daughters, who are still in Daraa but he has had no contact with them, after the prayer of Eid al-Fitr, that marks the end of the holy fasting month of Ramadan, at Zaatari Syrian refugee camp, in Mafraq, Jordan, Thursday, Aug. 8, 2013. (AP photo/Mohammad Hannon)

  • This image provided by Shaam News Network on Thursday, Aug. 22, 2013, which has been authenticated based on its contents and other AP reporting, purports to show mourners next to bodies of victims of an attack on Ghouta, Syria on Wednesday, Aug. 21, 2013. (AP Photo/Shaam News Network)

  • This image provided by by Shaam News Network on Thursday, Aug. 22, 2013, which has been authenticated based on its contents and other AP reporting, purports to show several bodies being buried in a suburb of Damascus, Syria during a funeral on Wednesday, Aug. 21, 2013. (AP Photo/Shaam News Network)

  • Columns of smoke rising from heavy shelling in the Jobar neighborhood in west Damascus, in Cairo, Syria, Thursday, Aug. 22, 2013. (AP Photo/Hassan Ammar)

  • In this citizen journalism image provided by the Media Office Of Douma City, which has been authenticated based on its contents and other AP reporting, a Syrian man mourns over a dead body after an alleged poisonous gas attack fired by regime forces, according to activists, in Douma town, Damascus, Syria on Wednesday, Aug. 21, 2013. (AP Photo/Media Office Of Douma City)

  • Syrian refugees cross into Iraq at the Peshkhabour border point in Dahuk, 260 miles (430 kilometers) northwest of Baghdad, Iraq, Tuesday, Aug. 20, 2013. (AP Photo/Hadi Mizban)

  • This citizen journalism image provided by the Local Committee of Arbeen which has been authenticated based on its contents and other AP reporting, shows a Syrian man reacts as he carries a dead body of a Syrian girl, after an alleged poisonous gas attack fired by regime forces, according to activists in Arbeen town, Damascus, Syria, Wednesday, Aug. 21, 2013. (AP Photo/Local Committee of Arbeen)

  • This citizen journalism image provided by the Local Committee of Arbeen which has been authenticated based on its contents and other AP reporting, shows Syrian citizens trying to identify dead bodies, after an alleged poisonous gas attack fired by regime forces, according to activists in Arbeen town, Damascus, Syria, Wednesday, Aug. 21, 2013. (AP Photo/Local Committee of Arbeen)

  • This citizen journalism image provided by the Local Committee of Arbeen which has been authenticated based on its contents and other AP reporting, shows dead bodies of Syrian citizens in Arbeen town, Damascus, Syria, Wednesday, Aug. 21, 2013. (AP Photo/Local Committee of Arbeen)

  • A Syrian family sits in a tent at Kawergost refugee camp in Irbil, 217 miles (350 kilometers) north of Baghdad, Iraq, Wednesday, Aug. 21, 2013. (AP Photo/Hadi Mizban)

  • Syrian refugees stand in a queue to receive free food at Kawergost refugee camp in Irbil, 217 miles (350 kilometers) north of Baghdad, Wednesday, Aug. 21, 2013. (AP Photo/Hadi Mizban)

  • Syrian refugees wait to receive a tent at Kawergost refugee camp in Irbil, 217 miles (350 kilometers) north of Baghdad, Iraq, Wednesday, Aug. 21, 2013. (AP Photo/Hadi Mizban)

  • Syrian refugees wait to receive a tent at Kawergost refugee camp in Irbil, 217 miles (350 kilometers) north of Baghdad, Iraq, Wednesday, Aug. 21, 2013. (AP Photo/Hadi Mizban)

  • Syrian refugees gather for food aid at Kawergost refugee camp in Irbil, 217 miles (350 kilometers) north of Baghdad, Iraq, Wednesday, Aug. 21, 2013. (AP Photo/Hadi Mizban)

  • Syrian refugees wait for food aid at Kawergost refugee camp in Irbil, 217 miles (350 kilometers) north of Baghdad, Iraq, Wednesday, Aug. 21, 2013. (AP Photo/Hadi Mizban)

  • A Syrian military soldier holds his AK-47 with a sticker of Syrian President Bashar Assad as he stands guard at a check point on Baghdad street, in Damascus, Syria, Wednesday, Aug. 21, 2013. (AP Photo/Hassan Ammar)

  • A Syrian military soldier holds his AK-47 with a sticker of Syrian President Bashar Assad and Arabic that reads, "Syria is fine," as he stands guard at a check point on Baghdad street, in Damascus, Syria, Wednesday, Aug. 21, 2013. (AP Photo/Hassan Ammar)

  • This citizen journalism image provided by the Local Committee of Arbeen which has been authenticated based on its contents and other AP reporting, shows a Syrian man receiving treatment, in Arbeen town, Damascus, Syria, Wednesday, Aug. 21, 2013. (AP Photo/Local Committee of Arbeen)

  • Syrian refugees cross into Iraq at the Peshkhabour border point in Dahuk, 260 miles (430 kilometers) northwest of Baghdad, Iraq, Tuesday, Aug. 20, 2013. (AP Photo/Hadi Mizban)

  • Syrian refugees cross into Iraq at the Peshkhabour border point in Dahuk, 260 miles (430 kilometers) northwest of Baghdad, Iraq, Tuesday, Aug. 20, 2013. (AP Photo/Hadi Mizban)

  • A general view of the Kawergost refugee camp in Irbil, 217 miles (350 kilometers) north of Baghdad, Iraq, Wednesday, Aug. 21, 2013. (AP Photo/Hadi Mizban)

  • In this image taken from video posted by Ugarit News, which has been authenticated based on its contents and other AP reporting, purports to show a fireball from an explosion at a weapons depot set off by rocket attacks that struck government-held districts in the central Syrian city of Homs on Thursday, Aug. 1, 2013. (AP Photo/Ugarit News via AP video)

  • Syrian refugees gather for food aid after cross into Iraq at the Peshkhabour border point in Dahuk, 260 miles (430 kilometers) northwest of Baghdad, Iraq, Tuesday, Aug. 20, 2013. (AP Photo/Hadi Mizban)

  • In this image taken from video obtained from the Shaam News Network, which has been authenticated based on its contents and other AP reporting, a Syrian man comforts a child injured by a missile strike in Raqqa, Syria, Wednesday, Aug. 7, 2013. (AP Photo/Shaam News Network via AP video)

  • Syrian refugees cross into Iraq at the Peshkhabour border point in Dahuk, 260 miles (430 kilometers) northwest of Baghdad, Iraq, Tuesday, Aug. 20, 2013. (AP Photo/Hadi Mizban)

  • In this citizen journalism Monday, Aug. 12, 2013, image provided by Aleppo Media Center AMC, which has been authenticated based on its contents and other AP reporting, buildings are seen damaged from the shelling of Syrian forces at Karm al-Jabal area in Aleppo province, Syria. (AP Photo/Aleppo Media Center, AMC)

  • In this citizen journalism Monday, Aug. 12, 2013, image provided by Aleppo Media Center AMC, which has been authenticated based on its contents and other AP reporting, Syrian rebels open fire as they battle against the Syrian forces in Aleppo, Syria. (AP Photo/Aleppo Media Center, AMC)

  • In this image released by the Syrian official news agency SANA, a Syrian army soldier stands behind his machine gun during a battle against the Syrian rebels at an unidentified location in Latakia province, Syria, Tuesday, Aug. 13, 2013. (AP Photo/SANA)

  • In this image taken from video obtained from the Shaam News Network, which has been authenticated based on its contents and other AP reporting, a Syrian man carries an injured child away from a missile strike in Raqqa, Syria, Wednesday, Aug. 7, 2013. (AP Photo/Shaam News Network via AP video)

  • In this image released by the Syrian official news agency SANA, a Syrian forces tank fires during a battle against the Syrian rebels at an unidentified location in Latakia province, Syria, Tuesday, Aug. 13, 2013. (AP Photo/SANA)

  • In this image taken from Sunday, Aug. 11, 2013, video obtained from the Sham News Network, which has been authenticated based on its contents and other AP reporting, a rebel fighter fires a gun in a valley in an unidentified location in Latakia province, Syria. (AP Photo/Sham News Network via AP video)

  • Mansour Mahameed, 26, from Daraa city in Syria, a former Free Syrian Army fighter who lost his leg last March after the Syrian troops bombing, prepares to sit for the Eid al-Fitr prayer that marks the end of the holy fasting month of Ramadan at Zaatari Syrian refugee camp in Mafraq, Jordan, Thursday, Aug. 8, 2013. (AP Photo/Mohammad Hannon)

  • Syrian refugees cross into Iraq at the Peshkhabour border point in Dahuk, 260 miles (430 kilometers) northwest of Baghdad, Iraq, Tuesday, Aug. 20, 2013. (AP Photo/Hadi Mizban)

  • In this image taken from video obtained from the Shaam News Network, which has been authenticated based on its contents and other AP reporting, a Syrian man carries an injured child away from a missile strike in Raqqa, Syria, Wednesday, Aug. 7, 2013. (AP Photo/Shaam News Network via AP video)

  • In this photo released by the Syrian official news agency SANA, dead bodies of Syrian rebels are seen on the ground, killed during ambush by Syrian forces near the Damascus suburb of Adra, Syria, Wednesday Aug. 7, 2013. (AP Photo/SANA)

  • In this image taken from video posted by Shaam News Network, which has been authenticated based on its contents and other AP reporting, purports to show a fireball from an explosion at a weapons depot set off by rocket attacks that struck government-held districts in the central Syrian city of Homs on Thursday, Aug. 1, 2013. (AP Photo/Shaam News Network via AP video)

  • This image posted on the official Facebook page of the Syrian Presidency on Thursday, Aug. 1, 2013 purports to show Syrian President Bashar Assad shaking hands with a soldier during Syrian Arab Army day in Darya, Syria. (AP Photo/Syrian Presidency via Facebook)

  • This image posted on the official Facebook page of the Syrian Presidency on Thursday, Aug. 1, 2013 purports to show Syrian President Bashar Assad walking with soldiers with during Syrian Arab Army day in Darya, Syria. (AP Photo/Syrian Presidency via Facebook)

  • In this image taken from video obtained from the Shaam News Network, which has been authenticated based on its contents and other AP reporting, a Syrian youths run away from the scene of a missile strike in Raqqa, Syria, Wednesday, Aug. 7, 2013. (AP Photo/Shaam News Network via AP video)