Updated

Syrian warplanes pounded a rebel-held town near the Lebanese border on Wednesday, activists said, in an apparent attempt to dislodge opposition fighters from the area and consolidate control over the border region.

Yabroud is the last rebel stronghold in Syria's mountainous Qalamoun region. Backed by Lebanon's Hezbollah fighters, the Syrian army has been on a crushing offensive there since early December.

The assault on Yabroud comes a day after a tense session between government officials and opposition leaders at peace talks in Geneva. The delegations met again Wednesday.

The Britain-based Syrian Observatory for Human Rights reported heavy fighting in Yabroud between troops loyal to President Bashar Assad and rebels trying to overthrow him. The Observatory, which has documented the conflict since it erupted in March 2011, said warplanes have carried out 10 airstrikes so far on Wednesday.

In Lebanon, preparations were underway to receive more Syrians fleeing the area.

An Associated Press reporter in the border town of Arsal saw several trucks and buses packed with people, clothes and other belongings rolling into Lebanon Wednesday.

A senior official with the town's administration told the AP reporter that up to 300 Syrians have crossed into Lebanon over the past 48 hours to escape violence on the other side of the border.

The official spoke on condition his name is not be used because he was not authorized to speak to reporters.

Yabroud has been controlled by the opposition for much of Syria's nearly 3-year-old conflict. Lebanese Sunni Muslims have moved through the town to join Syrian rebels in battles against Assad's forces, bringing in weapons and supplies for opposition fighters from Arsal, a town on Lebanese side of the border.

Hezbollah fighters have been key to the Syrian army's success in the border region.

In June, the Iran-backed group helped Assad's forces regain control of the town of Qusair. Its fall tipped the balance of power in the Syrian conflict in Assad's favor, though Hezbollah's public involvement in the civil war next door deepened sectarian tensions in Lebanon.

In the past weeks, several car bombs have exploded in Hezbollah strongholds in Beirut in apparent revenge attacks by Sunni militants for the group's involvement in Syria.

On Wednesday, security forces sealed off a section of a predominantly Sunni neighborhood of Corniche al-Mazra in west Beirut after an explosives-laden car was reported parked in the area. The troops dismantled the vehicle before the bomb, which contained 220 pounds of explosives, could go off, according to Lebanon's state news agency.

The National News Agency said investigators believe the explosives-packed car was to be driven to a southern suburb of Beirut, a Hezbollah stronghold, to be detonated there.

Lebanon's Mayadeen TV and Hezbollah's Al-Manar TV said the Syrian army has started "a wide-scale military operation in Yabroud" and that the troops were "advancing." In the early afternoon, Assad's troops took control of the village of Jarajir and surrounding hills on the Syrian side of the border.

In Syria, more civilians were expected to leave the embattled city of Homs before an extended cease-fire expires at midnight Wednesday, Syrian Red Crescent said in a statement.

The aid organization has been part of the relief effort in Homs since Friday, when the U.N.-brokered humanitarian truce went into effect. Its statement said the staff entered the city earlier Wednesday to deliver 190 food parcels and 190 bags of flour.

Also Wednesday, Russian Deputy Minister of Foreign Affairs Gennady Gatilov arrived in Geneva and met with U.N. mediator Lakhdar Brahimi who was pessimistic over any progress at the talks. On Tuesday, Brahimi declared that "we are not making much progress."

The three-way meeting included Brahimi, Gatilov and U.S. Undersecretary of State for Political Affairs Wendy Sherman is scheduled to be held in Geneva on Thursday to discuss the deadlock.