At least 36 people were killed and 50 injured in Israeli airstrikes on residential buildings and an industrial area in the central Syrian town of Palmyra, Syrian state media reported.
The SANA news agency quoted a military source as saying that Israeli jets struck from the direction of the Jordanian border to the south at around 13:30 (10:30 GMT).
A Britain-based monitoring group put the death toll at 41 and said the attacks targeted a warehouse that housed weapons and the families of fighters from Iran-backed militias.
The Israeli military said it had no comment on foreign reports.