Syrian army battle forces in key Damascus foothills
Syrian troops backed by fighters from Lebanon's Hezbollah on Sunday launched an assault to oust opposition forces from the foothills of the Qalamun mountains north of the capital, according to state television.
Elsewhere in the capital, fighters were due to withdraw "within hours" from the Palestinian refugee camp of Yarmouk, following a truce struck on Saturday evening to end deadly fighting, a Palestinian official said.
Forces loyal to Bashar al-Assad took parts of the strategic Qalamun region near the border with Lebanon in April, but some 2,000 fighters withdrew to the hills from where they have launched attacks.
Fourteen fighters from the Shiite Hezbollah group have been killed in the area over the past two weeks, the Syrian Observatory for Human Rights said.
Syria's state broadcaster showed footage of the troops, saying they had taken "some hills overlooking the Rankus plain and are pursuing terrorist groups who tried to infiltrate the region from Lebanon".
An officer interviewed by the channel said "the army has cut the route off to terrorist groups who try to return to the region from time to time. The operation is continuing until the whole of the Qalamun area has been cleansed.
"This land will be a cemetery for all terrorists who decide to return."
Assad's government refers to the armed opposition inside the country as "terrorists", without distinguishing between different groups.
Observatory head Rami Abdel Rahman said that "rebels hiding in the heights and in caves have been attacking army and Hezbollah positions for weeks after being pushed out of the region, which also prompted regime forces to withdraw".
He said the rebels had launched a counter attack "and succeeded in retaking their positions and expanding their presence".
Meanwhile, fighters were expected to exit the embattled Yarmuk camp in southern Damascus "within hours", a Palestinian official told AFP in the Syrian capital on Sunday.
Anwar Abdel Hadi, political director of the Palestine Liberation Organisation in Syria, said "the armed men will pull out of the camp, checkpoints will be dismantled and rubble removed".
The pullout is part of a truce agreed between the PLO and gunmen "with the approval of the Syrian government", he said, adding that the fragile ceasefire went into force at 1500 GMT Saturday.
In mid-February, a truce paved the way for the withdrawal of fighters from al-Qaeda's franchise in Syria, al-Nusra Front, from Yarmuk, but fighting flared again in March.
The extremists had accused regime forces besieging Yarmuk of violating the earlier ceasefire agreement.
Once home to 150,000 Palestinians as well as Syrians, Yarmuk has been under total army siege for the past year.
On Saturday, barrel bomb attacks by Assad forces on a number of towns and villages in Damascus killed 11 people.
Syrian Revolution General Commission said the bomb attack, which was carried out near the Ghouta district of Damascus, followed clashes between the Syrian forces and opposition groups.
Two soldiers loyal to Assad were killed prior to the attack, it said.
Since the Syria conflict began in March 2011, an estimated number of more than 162,000 people have been killed and millions displaced, but the UN has stopped updating its death toll for the country because an official count had become too difficult to verify.
At least 100,000 deaths were recorded in the last official count in July 2013.