Syria's air force struck rebel-held areas around Damascus and Aleppo Saturday, a monitoring group said, as face-to-face peace talks tentatively began in Switzerland.
The meeting in Geneva came after months of intense diplomacy aimed at bringing the two warring sides together, but the intense violence on the ground underscored the challenges ahead in trying to end the nearly three-year civil war.
Government warplanes fired rockets at Qadam in southern Damascus and Talfita to its north, said the Syrian Observatory for Human Rights, a Britain-based group with a network of sources inside the war-torn country.
Helicopters meanwhile struck Daraya, southwest of Damascus, using TNT-laden barrels, the group added.
Rebels battled troops loyal to President Bashar al-Assad on the frontlines surrounding several Damascus areas, including the besieged Yarmuk Palestinian refugee camp, it said.
In the north regime warplanes struck several parts of Aleppo, Syria's second city and onetime economic hub, swaths of which have been under rebel control since July 2012.
Since December 15, Aleppo has been the target of an aerial offensive that has killed hundreds, mostly civilians, the Observatory says, and on Friday 10 people were killed in barrel bomb attacks on the outskirts of the city.
Signup to our newsletter and follow us on Facebook and Twitter!
Rights groups have condemned the use of fighter jets and barrel bombs on opposition areas as "indiscriminate."
Aleppo-based activist Mohammad Wissam told AFP via Skype that the army has taken advantage of the fact that rebels have recently turned their guns against a feared jihadist group.
"The army has deployed en masse around the east of the city, and families residing in the area have started to flee for other safer neighbourhoods and villages," fearing an all-out assault, he added.
In Raqa city, meanwhile, which is the main stronghold of ISIL, the jihadist group arrested a man "for walking with his wife, who was not wearing the niqab," or full face veil, the Observatory said.
ISIL issued four statements earlier this week ordering women to wear the niqab in public, forbidding the sale of cigarettes and narghile (water pipe) products, banning music and making attendance of Friday prayers compulsory.
Once welcomed by Syrian rebels seeking to topple Assad, ISIL's abuses have turned much of the opposition against them.
In recent weeks, ISIL has consolidated its grip on Raqa city, the only provincial capital to fall out of regime control since the outbreak of Syria's uprising in March 2011.
More than 130,000 people have been killed in Syria in nearly three years, and millions more forced to flee their homes.