AFP's correspondent in Damascus said several consecutive blasts were heard at 4:00 am local time, followed by the sound of airplanes overhead. Smoke could be seen emerging from the northern and eastern edges of the capital.
It said three civilians were wounded in the Homs attacks but did not give a toll for Damascus or mention any combatant casualties.
Several missiles hit a research centre in Barzeh, north of Damascus, "destroying a building that included scientific labs and a training centre," SANA reported.
State media published images of a cloud of reddish smoke hanging over the capital and said that air defences were activated to block the attack.
But it said skies were clear over Aleppo in the north, Hasakeh in the northeast, and Latakia and Tartus along the western coast, where key Syrian and Russian military installations are located.
The joint operation came one week after a suspected chemical attack on an opposition-controlled town outside Damascus left more than 40 people dead.
The Organisation for the Prohibition of Chemical Weapons was set to begin its investigation inside the Eastern Ghouta town of Douma on Saturday, just hours after the strikes.
Syrian state media accused Western powers of trying to hinder the investigation with their attack.
"The three aggressors preempted the OPCW's mission in Ghouta, with the aim of hiding their lie," SANA said today.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)