By Stephen Kalin
BEIRUT, March 15 (Reuters) - Syrian soldiers entered eastern districts of the town of Yabroud, the last rebel bastion near the Lebanese border north of Damascus, on Saturday and advanced towards the main street, Al Mayadeen television said.
The Beirut-based station broadcast footage showing soldiers charging through a field towards an arched entrance of the town and a sign saying "Welcome to Yabroud". Gunfire could be heard as the soldiers advanced.
Capturing Yabroud would help President Bashar al-Assad choke off a cross-border rebel supply line from Lebanon. The town is near the highway linking Damascus to the former commercial hub of Aleppo in the north and to the Mediterranean coast in the west, where Assad's minority Alawite community is concentrated.
The Syrian Observatory for Human Rights monitoring group said the government was pounding some districts of Yabroud with improvised barrel bombs and shelling its outskirts.
The anti-Assad Observatory said heavy fighting was going between government forces supported by Lebanese Shi'ite militant group Hezbollah and rebel factions including the Nusra Front, al Qaeda's official branch in Syria, and the Islamic State of Iraq and the Levant (ISIL), an al Qaeda splinter group.
Thousands of people fled Yabroud, a town of about 40,000 to 50,000 people roughly 60 km (40 miles) north of Damascus, and the surrounding areas after it was bombed and shelled last month ahead of the government offensive.
The government has been making incremental gains along the highway as well as around Damascus and Aleppo in recent months, regaining the initiative in a conflict which entered its fourth year this month.
A senior commander in the Nusra Front was killed late on Friday on the outskirts of Yabroud during shelling and clashes with the army and Hezbollah fighters, the Observatory said.
Abu Azzam al-Kuwaiti was the deputy leader of the Nusra Front in Qalamoun, the mountainous zone between Damascus and the Lebanese border where Yabroud is situated.
He had been a principal negotiator in the prisoner exchange last week which secured the release of 13 Greek Orthodox nuns held by the Nusra Front since December, according ot the Observatory.
More than 140,000 people have been killed and 2.5 million have fled abroad as refugees in an increasingly sectarian civil war. The conflict began with mass street protests against Assad in March 2011 but turned into an armed insurgency after a violent security crackdown on demonstrators.