BEIRUT — Syrian troops backed by Hezbollah fighters pressed forward with their offensive in the country's opposition-held heartland on Friday, taking two small villages and entering a third near a strategic town that was captured by the government earlier this week, while the U.N. asked donor countries for $5.2 billion in humanitarian aid as it predicted the number of refugees could more than double by the end of the year.

Buoyed by Wednesday's victory in the strategic town of Qusair, pro-government forces have directed their efforts toward driving rebels from strategic areas to the north, including the cities of Homs and Aleppo.

Government forces faced little resistance Friday as they took control of the villages of Salhiyeh and Masoudiyeh, just north of Qusair, activists and the state news agency SANA said. On Thursday, the rebels also lost control of the nearby village of Dabaa.

The push brought Assad's troops to the edge of Buwaydah village, also north of Qusair, where most of the rebels who withdrew from Qusair took up positions and regrouped. State TV reported government troops broke into the village Friday night and were pursuing rebels there.

Fierce fighting in the area in the past three weeks has left dozens of rebels, troops and Hezbollah fighters dead.

Since joining the battle in Qusair in full force in April, Hezbollah, based in Lebanon, has helped tip the balance of power to Assad's side.

The acting head of the main opposition group, the Western-backed Syrian National Coalition, warned the growing role of Iranian-backed Hezbollah in the conflict was widening the sectarian divide and jeopardizing any hopes for peace talks.

"The intervention of Hezbollah starts to transfer the problem into a sectarian conflict, a sectarian war between Sunnis and Shiites," George Sabra told The Associated Press in an interview in Copenhagen. "The problem will (spread) all over the Middle East, to Lebanon, to Turkey, to Iraq, to Jordan and maybe to the Gulf."

"The problem is not between the Syrian people and the regime; it is between the Syrian people and invasion of Hezbollah and Iran," he added.

Hezbollah soldiers who back Assad's regime, he added, are now "all over the country" including in Aleppo and Damascus. His claims could not be independently verified, although activists have said that Hezbollah members were deployed in two Shiite villages in the northern Aleppo province.

Hezbollah fighters have also replaced Syrian troops at dozens of checkpoints surrounding Homs, according to Tariq Badrakhan, an activist in the city.

"Hezbollah is putting in all its weight," he said on Skype, citing residents in areas just outside the rebel-held old city.

The World Food Program said it has distributed urgent food aid to "vulnerable families" in Qusair – enough to feed 2,500 people – through the Syrian Red Crescent society on Thursday, marking the first time aid workers have entered the town in months. The U.N. Security Council also urged the regime to immediately allow humanitarian groups into Qusair to provide food and medical aid to civilians.

Sporadic clashes also broke out Friday in the Syrian area of Quneitra near the Israeli-controlled Golan Heights, a day after rebels briefly seized control of a border crossing to the area that was later recaptured by government troops. The fighting prompted Austria to announce it was withdrawing its peacekeeping contingent that is part of a U.N. force that patrols the Israeli-occupied area, heightening fears in Israel that Syria's civil war is increasingly spilling over its doorstep.

Russian President Vladimir Putin offered Friday to send Russian troops to the Golan to replace the Austrians. His offer was quickly shot down by Josephine Guerrero, a spokeswoman for the U.N. peacekeeping department. She said the disengagement agreement does not allow the participation of troops from a permanent member of the U.N. Security Council.

The Syrian Foreign Ministry, in a statement, called Austria's decision to withdraw its peacekeepers "regrettable" and said it welcomed Putin's offer to replace them with Russian troops.

The Syrian conflict started with largely peaceful protests against Assad's regime in March 2011, but later degenerated into a bloody civil war that has killed more than 80,000 people, according to United Nations officials.

The conflict has also raised tensions considerably in neighboring Lebanon, which is sharply split along sectarian lines and between supporters and opponents of Assad. The open involvement by Hezbollah fighters in Syria has further enflamed sectarian hatreds in Lebanon – a fragile country scarred by its own 15-year civil war – and led to recurrent and deadly street clashes between opposing groups.

In a rare statement, the Lebanese army warned Friday of "plots" to drag the country back to civil war.

The military vowed to take firm action against anyone who tries to tamper with the country's security, saying "the use of weapons will be met with weapons."

Also Friday, the U.N. launched its biggest humanitarian appeal ever to help millions of Syrians suffering the effects of the conflict. The $5.2 billion requested at an international conference in Geneva represents a sharp increase from the $3 billion the U.N. had previously estimated it would need this year, of which only $1.4 billion has so far been pledged.

"The situation has deteriorated drastically," said Valerie Amos, the U.N.'s top humanitarian official. The number of Syrian refugees in neighboring countries could more than double to 3.5 million by the end of the year, U.N. refugee chief Antonio Guterres said at a news conference in Geneva.

Meanwhile, French president Francois Hollande called on Friday for the release of two French journalists, Didier Franšois and photographer Edouard Elias, who are missing in Syria, declining to provide details.

"Their lives are at risk, so I cannot say anything more," Holland told reporters during a state visit to Tokyo. "I want them released as soon as possible."

___

Associated Press writers Jan M. Olsen in Copenhagen, Denmark, Edith M. Lederer at the United Nations and Frank Jordans in Berlin contributed to this report.

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