Syria accused Israel of staging an air raid on a military research center on Wednesday.
The Syrian army accused Israel of launching a dawn strike targeting a military research centre in Jamraya, near Damascus, in a statement carried by state news agency SANA and quoted by AFP.
"Israeli fighter jets violated our airspace at dawn today and carried out a direct strike on a scientific research center in charge of raising our level of resistance and self-defense," the general command said.
The warplanes entered Syria's airspace via Mount Hermon, Jabal el-Sheikh in Arabic, at low altitude and under the radar, the army said, adding that two site workers were killed.
"They... carried out an act of aggression, bombarding the site, causing large-scale material damage and destroying the building," state television quoted the military as saying.
The army denied reports Israeli forces had launched a strike overnight on a weapons convoy from Syria near the border with Lebanon.
The United States declined to comment on the reported strike by Israel, whose military intelligence chief Aviv Kochavi is currently in Washington for talks with top US general Martin Dempsey.
"I'd refer you to the government of Israel for questions about deliberations or actions that they may or may not have taken," White House spokesman Jay Carney said.
Earlier reports said that Israel had struck a convoy carrying Russian-made antiaircraft missiles. It is not clear at this point which report is the more accurate one, and what actually happened last night.