The Syrian military said on Thursday its air defences fired on Israeli aircraft that violated its airspace, forcing the planes to flee.

The Israeli aircraft broke the sound barrier and "dropped ammunition" over deserted areas of northern Syria overnight, the spokesman was quoted by the official Syrian Arab News Agency.

"We warn the Israeli enemy government against this flagrant aggressive act, and retain the right to respond in an appropriate way," the Syrian spokesman said.

The two countries technically remain at war since the Six-Day War in 1967, during which Israeli forces seized the Golan Heights from Syria.

It was not clear if Syria was accusing the Israelis of using warplanes or some type of other aircraft such as drones.

"The Israeli enemy aircraft infiltrated into the Arab Syrian territory through the northern border, coming from the Mediterranean heading toward the eastern region, breaking the sound barrier," the spokesman said.

"Air defence units confronted them and forced them to leave after they dropped some ammunition in deserted areas without causing any human or material damage."

Israel's army said it was looking into the report.

Israel acknowledges flying over Lebanon routinely, but it is unclear how often its aircraft fly over Syria.

Israel and Syria have accused each other of preparing for war amid months of cross-border tension and troop escalation near the Golan Heights.

Last June, Israeli warplanes flew over Syrian President Bashar al-Assad's palace in the country's northwest in what the Israeli military said was an attempt to pressure Syria into expelling a top Hamas official from Damascus.

With files from the Associated Press