Turkey said that Syria had shot down one of its military planes over the eastern Mediterranean as a search and rescue operation was still underway late last night to find the aircraft's missing pilots.
The shooting of the fighter jet was confirmed in a late-night statement from the Syrian military, carried on the state-run news agency Sana and saying that the aircraft was shot down over Syrian waters.
"Our air defences confronted a target that penetrated our air space over our territorial waters pre-afternoon on Friday and shot it down. It turned out to be a Turkish military plane," the statement said.
While the Syrian statement appeared at pains to indicate that the anti-aircraft strike was ordered without it being known that the aircraft was Turkish, the incident is likely to add to the already serious tensions between the two countries. Turkey has called for President Bashar al-Assad to step down, is sheltering 32,000 Syrian refugees and its eastern region is a conduit for arms to rebels forces.
The alarm had been raised earlier when the F-4 jet which had taken off from an military base in eastern Turkey with a crew of two aboard dropped out of radio contact. Syrian vessels appear to have joined the search operation.
A statement issued last night by the office Turkish Prime Minister Recep Tayyip Erdogan after a meeting he held with his cabinet and military chiefs said: "As a result of information obtained from the evaluation of our concerned institutions and from within the joint search and rescue operations with Syria, it is understood that our plane was brought down by Syria."
The statement added that Turkey would decide on its response to the incident once all of the details became clear. It was not immediately clear whether earlier reports that Syria had apologised for the crash were true.
Amid a series of conflicting reports over the fate of the F-4 jet, which took off from Erhac airbase in eastern Turkey yesterday morning, there had been earlier, unconfirmed suggestions that it had been shot down by Syrian air defences.
This claim was made by the Lebanon-based pro-Iranian Al-Mayadeen television station. The BBC said that eye-witnesses in the northern Syrian town of Latakia had earlier told its Arabic service that Syrian air defences shot down an unidentified aircraft near the town of Ras al-Baseet.
The aircraft vanished as Syrian opposition activists said rebels had killed 26 members of a mainly Alawite militia loyal to President Assad and the Russian foreign minister Sergei Lavrov said he had urged Syria to do a "lot more" to implement a UN peace plan.
Turkey's state-run TRT television had said earlier that the Turkish coast guard, reinforced from the air by helicopters and a plane, were searching the area and that three Syrian vessels joined it.
Mr Lavrov indicated after talks with his Syrian counterpart, Walid al-Moualem, Syria was prepared to withdraw its forces from cities in line with former UN Secretary-General Kofi Annan's plan provided the "armed opposition" did likewise.