The mandate of the U.N. observer mission in Syria ends Sunday, with the country no closer to a cease-fire than when monitors arrived four months ago. But the United Nations will still maintain a presence in the war-torn country after the 300 military observers leave. "We will continue the search to move from violence to dialogue," said the mission's leader, Lt. Gen. Babacar Gaye. The U.N. Supervision Mission in Syria was tasked with monitoring a cease-fire that was agreed to by the government and rebels in April. But the cease-fire never took hold, and violence soon surged. Such violence continued even on Sunday, when much of the country was celebrating Eid al-Fitr. The holiday marks the end of fasting during Ramadan, Islam's holiest month. The Homs province village of Ghanto saw its "fiercest shelling with mortars and heavy machine guns on the village," the opposition Local Coordination Committees of Syria said. Meanwhile, Syrian state-run TV aired footage of Eid prayers attended by the Syrian leadership in Damascus, including President Bashar al-Assad. But Vice President Farouq al-Sharaa -- whom rebels say has defected from the regime -- was noticeably absent from the service. A spokesman for the rebel Free Syrian Army said Saturday that al-Sharaa has fled the regime. Syrian state-run TV did not explicitly say if al-Sharaa had defected, but said the vice president's office issued a statement saying al-Sharaa "has never at any moment thought of leaving the homeland to whatever direction." As of Sunday morning, al-Sharaa's location was not known. If al-Sharaa did defect, it would mark the highest-level departure from al-Assad's regime yet. Such a defection would follow a stream of resignations by Syrian officials in recent weeks, including Republican Guard Brig. Gen. Manaf Tlas and Prime Minister Riyad Hijab. Like al-Sharaa, the men are Sunni Muslims who held top posts in a government dominated by the country's Alawite minority. Rafif Jouejati, a spokeswoman for the LCC opposition network, said al-Sharaa's defection would suggest "the regime is collapsing very quickly." "If confirmed, (this) represents yet another high-level official who sees that the al-Assad regime is a sinking ship," she said. "I expect to see additional defections in both the military and civilian sectors in the coming days." Observers view al-Sharaa's power and influence as more significant than that of the prime minister, who only served in the post for weeks. Al-Sharaa has more clout as a prominent member of the regime's old guard who served as foreign minister under al-Assad and his late father, Hafez, for more than 20 years. Louai Miqdad, a spokesman for the rebel Free Syrian Army, said al-Sharaa left Damascus more than a week ago and fled to Daraa to try to make sure his relatives, close proteges and other officials would be safe. Al-Sharaa is from Daraa province, the area bordering Jordan where the regime's violent crackdown against protesters began in March 2011. The rebel spokesman said he thinks the Syrian regime intensified attacks in Daraa province recently to try to assassinate al-Sharaa before he left the country. "Farouq al-Sharaa did defect, but we were trying to get him through to Jordan," Miqdad told CNN on Saturday. He said rebel army leaders "lost communications with our commanders in Daraa who were trying to get him to cross the borders to Jordan," expressing concerns government forces may have detained some of al-Sharaa's relatives to compel him to surrender. By Saturday, the state-run Syrian Arab News Agency had removed al-Sharaa's profile from its website. Andrew Tabler, a Syria expert at the Washington Institute for Near East Policy, said al-Sharaa may have defected "because the battle now has become so sectarian," with an opposition dominated by Sunnis fighting against pro-regime Alawites. During Arab League meetings in recent months, al-Sharaa was mentioned as a successor to al-Assad under a transition plan similar to the one in Yemen, where the president left office and the vice president took over. Jouejati, from the opposition LCC, notes it has been widely reported that al-Sharaa lost relatives in Daraa during the uprising and has been "under near-constant surveillance."