BEIRUT: Syrian forces backed by fighters from Hezbollah entered the rebel bastion of Yabroud near the Lebanese border Friday, Syrian army and Hezbollah sources said, triggering fierce street-to-street fighting.
"The Syrian army Friday entered the town of Yabroud north of Damascus from the east, and advanced along the town's main street," an army source said.
"The rebels are fleeing toward Rankus village" to the south. "If their flight continues, the capture of the city is only a matter of days."
State television confirmed the army entered the city: "Syrian army units have advanced in the Yabroud area and now control its eastern approaches and northeastern boundary."
The broadcaster said the offensive had caused a "breakdown in the ranks of terrorist groups," the government term for rebels battling President Bashar Assad.
Hezbollah, spearheading the fight to dislodge insurgents from Yabroud, and Syrian forces "drove the rebels off the hill of Aqaba" outside the town, said the U.K.-based Syrian Observatory for Human Rights, which relies on civilian, medical and military sources for its information.
"This is the closest point ever reached by Hezbollah and the army" to Yabroud, Observatory chief Rami Abdel-Rahman told AFP.
"Fierce fighting is also taking place on the northern edge, between the town of Sahel and Yabroud," he said.
"They want to completely encircle the Yabroud rebels to dislodge them."
But it denied that rebels were retreating, insisting reinforcements were on the way.
An activist in the region confirmed to AFP the army and Hezbollah had taken a position at Aqaba some 5 kilometers from Yabroud.
The battle for the town is vital for Hezbollah, which first admitted its fighters were fighting alongside Assad's forces in spring 2013.
Hezbollah wants to sever a key rebel supply line to the Sunni Arsal across the border in eastern Lebanon.
It says car bombs that have been used to attack it were loaded with explosives in Yabroud and driven via Arsal to their targets in Lebanon.
On another front in the complex struggle pitting regime loyalists against mainstream rebels and rebels against jihadists of the Islamic State of Iraq and Greater Syria, ISIS Friday withdrew from Idlib province in the northwest and Latakia in the west, the Observatory said.
"ISIS is no longer able to defend his fighters" in these areas because of clashes with other rebel factions, it said, adding the withdrawal began a week ago.
"Rebel brigades were about to engage them," the Britain-based NGO said.
Spurned because of its abuses of civilians and extreme interpretation of Islam, ISIS had already pulled out of several areas in the northern province of Aleppo since January.
The conflict between mainstream insurgents and jihadists has killed 4,000 people since January, says the Observatory, which estimates a total death toll of more than 146,000 in three years of fighting in Syria.
Aymenn Jawad al-Tamimi, a fellow at U.S.-based think tank the Middle East Forum, said that following the withdrawal, ISIS was likely to focus on strengthening its position in Raqqa, Hasaka and eastern Aleppo provinces.
"Basically, what's happening is that each side is consolidating its own positions. So really, it's heading to a stalemate and each side builds its influence in its respective areas."
Another activist based near the Turkish border said a number of ISIS fighters, most of them foreign, were reported to have crossed the border in recent days.
In a separate incident, the Syrian army killed 20 militants in an ambush in Tal Kalakh, a village 40 km west of Homs, a military source told Reuters. Lebanon's Al-Manar television channel also reported the incident.
The source said the attack happened near a customs checkpoint close to the border with Lebanon, about 4 km from the village.
On the diplomatic front, U.N. Secretary-General Ban Ki-moon said Russia and Iran should pressure their ally in Damascus to restart peace talks aimed at ending the three-year civil war.
The U.N.-led talks, dubbed Geneva II, broke down on Feb. 15 when a second round ended, and no new date was set for them to reconvene.
U.N. and Arab League envoy Lakhdar Brahimi said earlier this week that the Syrian government was engaged in "delaying tactics" aimed at slowing the resumption of the talks to end the conflict.
"Anyone who has influence, the Russian government or the Iranian government, may impress upon the Syrian authorities so that they will come with a more constructive attitude to the Geneva conference."
Ban was speaking after an informal meeting of the U.N. General Assembly attended by Brahimi, who is to head to Tehran Sunday.
"Iran is one of the important regional countries who can play an important role, including impressing upon the Syrian authorities to come to the Geneva conference in a more constructive way," he said.