Last week, in a rare confirmation of such operations, Israel said its warplanes carried out a "very intense" attack against Iranian forces and Syrian army targets in Syria.
At least 44 people were killed on Saturday and scores injured in a double bombing attack on buses of Shia pilgrims parked outside a cemetery here, a war monitor based in Britain said.
The Syrian Observatory for Human rights said the two explosions happened in the historic centre of Bab-al-Saghir cemetery area here, Efe news reported.
The Observatory did not rule out that the number of casualties could rise, as several of the injured were said to be in serious condition.
In the hours before the bombings government forces attacked rebel positions with artillery in the rebel-controlled Qabun area outside the Syrian capital, though no casualties were reported, the Observatory said.