BEIRUT — Syrian activists said rebels shot down a government warplane over the northern province of Idlib on Thursday, the second time in a week that opposition fighters claimed to have brought down an aircraft in the escalating civil war.

Two activist groups, The Local Coordination Committees and the Britain-based Syrian Observatory for Human Rights, said the plane was seen crashing near the Abu Zuhour air base. Idlib-based activist Alaa al-Din said rebels shot it down with heavy machine guns.

A video broadcast on the pan-Arab satellite station Al-Arabiya shows what appears to be a person parachuting and rebels cheering and claiming he was the pilot. The video's authenticity could not be verified.

The government had no immediate comment, and the report couldn't be independently confirmed. But a brief video clip posted by an Idlib-based rebel group showed the body of a man in an olive-green pilot overall with an apparent head wound. A short distance away lay what appeared to be a white parachute.

The authenticity of the video, dated Aug. 30, could not be independently verified.

Over the past month, President Bashar Assad's regime has been relying much more heavily on air power, escalating the fight with rebels as its ground forces have been stretched thin fighting on many fronts including Syria's two largest cities – Damascus and Aleppo. The military has conducted air raids on the northern regions of Idlib and Aleppo near Turkey as well as the eastern province of Deir el-Zour.

The increased use of air power is likely a factor in the high daily death tolls, which activists say have been averaging 100-250 lately.

Later in the day, Human Rights Watch said government forces have killed scores of civilians over the past three weeks by bombarding at least 10 areas where they were lining up at bakeries near and around Aleppo.

"Day after day, Aleppo residents line up to get bread for their families, and instead get shrapnel piercing their bodies from government bombs," researcher Ole Solvang said in a statement after returning from the northern city.

The rebels' claim of shooting down the warplane on Thursday was the third time this month they said they have brought down a government aircraft.

Earlier this week, the opposition fighters said they shot down a helicopter in the Damascus neighborhood of Jobar while the government confirmed a chopper crashed in nearby area of al-Qaboun. On Aug. 13, rebels claimed to have shot down a regime MiG-23 warplane and captured the pilot in Deir el-Zour. Syria says the pilot ejected after a technical malfunction in the fighter jet.

If the rebel claims are confirmed, it would be another blow to Assad's regime, which has been struggling to put down rebel challenges around the country even though its firepower is far superior to the opposition's.

Rebels appear to be targeting air bases with increasing frequency.

Earlier in the day, the Observatory reported explosions inside the Abu Zuhour air base in Idlib, near where the plane was reported to have been shot down. It added that rebels have captured parts of the compound.

On Wednesday, state news agency SANA reported that government forces repulsed a major rebel attack on a helicopter military base of Taftanaz, also in Idlib province.

Idlib, which borders Turkey, has been one of the major rebel strongholds since last year. Although government troops control the provincial capital, which carries the same name as the province, rebels move freely in towns and villages in the district.

In Iran, Egyptian President Mohammed Morsi described the Syrian regime as "oppressive" and called for it to transfer power to a democratic system. He was speaking at the opening of a summit of the 120-member Nonaligned Movement in Tehran.

Morsi's comments angered the Syrian delegation, which walked out in protest, according to Syria's state-run media.

Syrian Foreign Minister Walid al-Moallem, who is also in Tehran, was quoted by the state-owned Al-Ikhbariya TV as saying: "Morsi's comments violated the traditions of the summit and are considered interference in Syrian internal affairs." He also accused Morsi of "instigating blood shedding in Syria."

Iran is Syria's closest ally in the Middle East.

Morsi is an Islamist from the Muslim Brotherhood, the most powerful political force to emerge from last year's uprising that ousted longtime authoritarian leader Hosni Mubarak. The Sunni fundamentalist group opposes Shiite Iran's staunch backing of the Syrian regime and its lethal crackdown on the largely Sunni opposition. Assad belongs to the minority Alawite sect, an offshoot of Shiite Islam.

Assad, speaking in a rare TV interview broadcast on Wednesday, said his armed forces will need time to defeat the rebels – an acknowledgement of the difficulties the military is facing in winning the civil war.

A member of Syria's main opposition group said his comments aimed to explain his security forces' failure in putting down the rebellion. British-based opposition activist Ausama Monajed, who is a member of the Syrian National Council, said in a telephone interview that Assad's statements tried to "justify the failure of the security solution."

"He is trying to boost the morale of his supporters. He is trying to justify the failure of the military solution that has been going on for months," Monajed said. "His comments were addressed to his constituency."

Activists estimate more than 20,000 people have been killed since the uprising against Assad's began more than 17 months ago.

Earlier on HuffPost:

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  • Syrian Regime

    Despite major defections and a July 18. explosion in Damascus that killed four top generals, including President Bashar Assad's brother-in-law, the regime's inner circle is still powerful and united against the opposition. Assad's inner circle includes his younger brother, Maher, who commands the forces in charge of protecting the capital. It also includes the heads of the four intelligence agencies playing a major role in the crackdown. Although regime forces lost parts of the northern city of Aleppo, Syria's largest, government troops still control most cities, while the opposition dominates large parts of the countryside. <em>Caption: This June 13, 2000, file photo shows Syrian President Bashar Assad, right, his brother Maher, center, and brother-in-law Major General Assef Shawkat, left. (AP Photo, File)</em>

  • Free Syrian Army

    The main rebel fighting force for more than a year, the Free Syrian Army includes lightly-armed volunteer militiamen and defectors from Assad's military. Its overall strength and structure is unclear, but tens of thousands are believed be loyal to the group. The rebels have control over some northern areas, allowing movement of fighters and supplies from Turkey and Lebanon. Anti-Assad forces have failed to maintain any strategic footholds in big cities, being driven back from key neighborhoods in Homs earlier this year and now apparently losing ground in the largest urban center, Aleppo. The battles also suggest only weak direction from central commanders - including Turkey-based Free Syrian Army leader Riad al-Asaad. <em>Caption: In this citizen journalism image provided by Shaam News Network SNN, taken on Sunday, Aug. 12, 2012, Free Syrian Army soldiers pose for a photograph, in Sarmada, Idlib province, northern Syria. (AP Photo/Shaam News Network, SNN)</em>

  • Syrian National Council

    Based in Istanbul, the SNC has emerged as the main political opposition to Assad and has pushed for international recognition as the legitimate representative of the uprising, despite rifts with other Syrian factions. The group also has been hit by internal feuds that have led some senior members to quit. The current leader, Abdelbaset Sieda, is a Swedish-based activist for Syria's minority Kurdish community. The SNC has gained support from many countries in the West and Arab world, but it has not galvanized international backing, and critics complain its senior leadership is made up mostly of exiles out of touch with their homeland. <em>Caption: The members of the Syrian National Council and its head Abdulbaset Sieda, center, arrive for a meeting with Turkey's Foreign Minister Ahmet Davutoglu in Ankara, Turkey, Monday, July 23, 2012.(AP Photo/Burhan Ozbilici)</em>

  • The National Coordination Committee for Democratic Change

    A rival to the SNC, the National Coordination Committee is led by opposition figures inside Syria, many of them former political prisoners. SNC members accuse the group of being far too lenient and willing to engage in dialogue with the regime. In turn, the National Coordination Committee accuses the SNC of being a front for Western powers and willing to open the door to the Muslim Brotherhood and other conservative Islamist factions. <em>Caption: Member of the National Coordination Committee for Democratic Change, Morhaf Mickael speaks during a meeting of Syrian opposition parties in Brussels on Sunday, June 24, 2012. (AP Photo/Virginia Mayo)</em>

  • International Alliances

    On Assad's side are traditional Shiite allies Iran and Lebanon's Hezbollah. <em>Caption: In this photo released by the Syrian official news agency SANA, Iran's Supreme National Security Council, Saeed Jalili, meets with Syrian President Bashar Assad in Damascus, Syria, Tuesday, Aug. 7, 2012. (AP Photo/SANA)</em>

  • International Alliances

    The regime also has important political cover from Russia and China, which have used their Security Council vetoes to prevent U.N. sanctions on Syria. <em>Caption: In this Jan. 25, 2005 file photo, Syrian President Bashar Assad, left, and Russian President Vladimir Putin shake hands during a signing ceremony in the Kremlin, Moscow. (AP Photo/Sergei Chirikov)</em>

  • International Alliances

    The rebels have built an array of regional support that includes the wealthy Gulf states - led by Iran rival Saudi Arabia - and neighboring Turkey, which offers key supply routes. The West also backs the rebel forces, but has so far opposed mobilizing international military support similar to the NATO-led airstrikes that helped topple Moammar Gadhafi's regime in Libya. <em>Caption: From left, Bahrain's Foreign Minister, Sheik Khalid bin AhmedI bin Mohammed al-Khalifa, Saudi Arabia's Foreign Minister Prince Saud al-Faisal, his Turkish counterpart Ahmet Davutoglu and United Arab Emirates' Sheikh Abdullah bin Zayed al-Nahayan seenduring a group photo during the Gulf Cooperation Council (GCC) Foreign ministers meeting in Istanbul, Turkey, Saturday, Jan. 28, 2012 (AP Photo)</em>

  • Foreign Fighters

    Syria has drawn foreign fighters just as other recent conflicts such as Iraq and Afghanistan. No credible count on them exists, but anecdotal evidence suggests foreigners are coming to fight Assad. Rebel commanders downplay the presence of foreign fighters, saying their cause is a purely Syrian uprising. Mohammed Idilbi, a Syrian activist based in Turkey, says foreign ranks include Libyans, Yemenis, Tunisians and Lebanese. On Saturday, Syria's official SANA news agency claimed four Libyans were among rebels killed in Aleppo. <em>Caption: In this Sept. 18, 2011 file photo, former rebel fighters celebrate as smoke rises from Bani Walid, Libya, at the northern gate of the town. (AP Photo/Alexandre Meneghini, File)</em>

  • Extremists

    U.S. officials and others worry that Syria could become a new foothold for insurgents inspired by al-Qaida. Assessing the degree of radical Islamic ideology in the civil war is impossible, but at least one group, the al-Nusra Front, has emerged and declared allegiance to the Free Syrian Army. Al-Nusra, or Victory, has claimed responsibility for several high profile attacks, including a double suicide bombing in March that killed 27 people in Damascus and the execution-style killing of a Syrian television presenter who was abducted in July. On Friday, U.S. intelligence officials said al-Qaida has advanced beyond isolated pockets in Syria and now is building a network of well-organized cells that could include several hundred militants. <em>Caption: This photo shows Al-Qaida's new leader Ayman al-Zawahiri in a still image from a web posting by al-Qaida's media arm, as-Sahab, Wednesday July 27, 2011. Al-Qaida's new leader has lauded protesters in Syria for seeking to topple the regime of President Bashar Assad. (AP Photo/IntelCenter) </em>