The Jamaraya region near Damascus has been the target of Israeli fighter jets according to the Syrian Observatory for Human Rights.
"Israeli planes targeted the Jamaraya region near Damascus including a scientific research centre and warehouses where weapons and ammunition of the regime and its allies were stocked," Rami Abdel Rahmane, director of the Britain-based monitoring group told AFP.
The exact target was not immediately identified.
An AFP correspondent in the capital also heard loud explosions.
"Our air defences blocked an Israeli missile attack on one of our positions in Damascus province and downed three of the targets," Syrian state media said.
Israel has acknowledged carrying out airstrikes in Syria since the outbreak of the bloody war in the country six years ago to stop arms deliveries to Hezbollah forces.
Israel said in October it had attacked Syrian government artillery after fire from across the armistice line hit the Israeli-occupied Golan Heights, and warned it would step up such retaliation in the future.
