Syrian troops have captured much of the rebel stronghold of Qusayr, in central Homs province, squeezing opposition fighters into the north of the strategic town, a military officer told AFP on Friday.
The Syrian Observatory for Human Rights watchdog said regime forces backed by members of Lebanon's Hezbollah militant group were bombing northern areas of the city, encircling rebel fighters there.
"The armed men are surrounded on all sides, there is no escape for them now," the officer told an AFP journalist accompanying army forces in the embattled town.
The regime uses the term "armed men" to refer to the rebel forces fighting to overthrow Syrian President Bashar al-Assad.
"The battle will continue until the complete liberation of Qusayr. We're in the second and penultimate phase of the fight," the officer said.
The Syrian army, backed by Hezbollah fighters, began on Sunday their assault on Qusayr.
They advanced into the south, east and west of the city, quickly claiming the municipality building in the centre of town.
The eastern part of the town, which has been abandoned by residents, has effectively been transformed into a military barracks, the AFP journalist said.
Armoured vehicles, military positions and fortifications can been seen in every street and on every corner.
Soldiers are posted on all the buildings overlooking the northern part of the town.
"There are many snipers who are trying to infiltrate buildings to monitor army movements in the secured areas," another army officer says.
At the entrance to a bakery, soldiers drink coffee and smoke cigarettes, while another group keeps a close eye on the main road, "to stop any infiltration by armed men," one of them said.
The army says it now controls the road linking Qusayr to Baalbek -- the largest city in eastern Lebanon and a stronghold of the Hezbollah movement which is allied to the Syrian regime.
Qusayr is strategically important for both the rebels and the regime.
For the rebels, the town of 25,000 people is a conduit on a route along which weapons and fighters arrive from Lebanon.
The regime wants to control the town to deny the rebels their strategic prize and also keep open the road between Damascus and the coast, which runs by Qusayr.
The Observatory reported violent clashes in the areas of Hamdiyeh and Arjuneh, as well as Dabaa airport, north of the city of Qusayr.
"The regime forces are trying to isolate Dabaa airport from the town to completely encircle the rebel groups," Observatory director Rami Abdel Rahman told AFP.
Hezbollah, meanwhile, "is using heavy artillery and mortars" in the fight against the rebels, he added.
The Observatory said at least 67 people had been killed across Syria on Friday, including 18 soldiers, 17 civilians and 32 rebel fighters.