The Syrian army said Israeli jets have attacked a military base in the west of the country, amid reports of a strike on a suspected chemical weapons site.
A statement said rockets fired from Lebanese airspace hit the site near Masyaf, killing two soldiers.
Arab media and a monitoring group reported that a chemical weapons production facility was targeted.
An Israeli military spokeswoman declined to discuss the reports, saying it does not comment on operational matters.
Israel has sporadically carried out air strikes on sites in Syria in recent years.
It recently accused Syria of allowing Israel’s arch-enemy Iran to build missile factories there and said it aims to thwart the transfer of advanced weaponry from Syria to the Iranian-backed Lebanese militant group Hezbollah.
The Syrian army said rockets struck the base near Masyaf, about 35km (22 miles) west of the city of Hama, at 02:42 on Thursday (23:42 GMT on Wednesday), causing “material damage” and the deaths of two personnel.
It accused Israel of attacking “in a desperate attempt to raise the collapsed morale” of the jihadist group Islamic State (IS) and warned Israel about “the dangerous repercussions of such hostile acts on the security and stability of the region”.