Syrian air force strikes killed at least 70 people in an opposition district outside Damascus following rocket attacks by rebels that had hit the government-controlled centre of the Syrian capital, a monitoring group said on Friday.
The Syrian Observatory for Human Rights, which monitors violence in Syria, said the air force conducted 60 strikes on the Eastern Ghouta district on Thursday and during the night. Twelve children and 11 fighters were among the dead, it said.
High death tolls from air force attacks are not rare but the Observatory said the focused barrage was a response to rocket attacks by Islam Army insurgents on Thursday, which killed 10 people in Damascus.
A message on Thursday on a Twitter account thought to belong to Islam Army chief Zahran Alloush said Thursday's rocket attack was a taste of what the Syrian military had done to Eastern Ghouta. Alloush described Damascus as a "military zone" and said his group would respond to any air force strikes.
Islam Army was formed by a merger of rebel factions in 2013 and has received backing from Saudi Arabia.
The U.N. says 200,000 people have been killed since 2011 in Syria's civil war, which started with peaceful protests against President Bashar al-Assad. The protests became an armed uprising after Assad's forces cracked down on demonstrators.