Syrian activists said government airstrikes Wednesday near Damascus killed at least 27 people.
The Britain-based Syrian Observatory for Human Rights, which monitors violence in the country, said the strikes hit several towns in the Eastern Ghouta region and also left at least 120 people wounded.
The airstrikes followed shelling in Damascus by rebel fighters that the Observatory said killed at least one person and wounded 20 others. Syria's state-run SANA news agency blamed "terrorists" for mortar and rocket fire, saying the shelling killed five civilians and left 55 wounded.
The government has routinely referred to rebels as "terrorists" throughout the conflict that began in March 2011 as peaceful protests before exploding into a civil war that has left more than 240,000 people dead. Another 11.6 million people have been forced from their homes, according to the U.N.
Wednesday's violence came as Iranian Foreign Minister Mohammad Javad Zarif was due to visit Damascus to discuss a proposal to halt the fighting in Syria. He talked about the plan during a stop Tuesday in Lebanon where he met with the leader of the militant group Hezbollah.
Syrian troops have been joined by Hezbollah fighters, including in Idlib province where the pro-government forces began a 48-hour ceasefire with rebels Wednesday in the town of Zabadani and two villages, Foua and Kfarya.
The Observatory said the two sides are negotiating the withdrawal of rebels from Zabadani, near the Lebanon border, as well as the end of a siege against the villages.