Turkish Deputy Prime Minister Bulent Arinc said today that the jet shot down yesterday by Syria was not a warplane but a reconnaissance aircraft, state television TRT reported.
It was not immediately clear where Arinc, who is one of four deputy prime ministers and also the government's spokesman, was speaking. Turkish media reported the downed jet was an F-4 Phantom, a supersonic jet fighter which can also carry out reconnaissance operations.
Earlier Turkey promised to do "whatever necessary" in response to Syria's shooting-down of the plane, but did not immediately contest an assertion by Damascus that the jet had been in its airspace at the time.
The downing of the aircraft, at a point close to the sea borders of both countries, provided a demonstration of Syria's formidable Russian-supplied air defences; one of the many reasons for Western qualms about any military intervention to halt bloodshed in the country.
Ankara's once-friendly relations with Damascus had already turned icy over President Bashar al-Assad's violent crackdown on a 16-month-old revolt, but signals from both sides suggested neither wanted a military confrontation over the incident.
"It is not possible to cover over a thing like this, whatever is necessary will be done," Turkish President Abdullah Gul said, according to state news agency Anatolia, adding that Ankara had been in telephone contact with Syrian authorities.
He said it was routine for fast-flying jets to cross borders for a short distance and that an investigation would determine whether the F-4 fighter was brought down in Turkish airspace.
Syria's military said the Turkish aircraft was flying low, just one kilometre off the Syrian coast, when it was shot down.
"The navies of the two countries have established contact. Syrian naval vessels are participating along with the Turkish side in the search operation for the missing pilots," it said.
With the second biggest army in NATO, a force hardened by nearly 30 years of fighting Kurdish rebels, Turkey would be a formidable foe for a Syrian military already struggling to put down a popular uprising and an increasingly potent insurgency.
Turkish Prime Minister Tayyip Erdogan chaired an emergency security meeting on last night after which his office said it is "understood" that Syria had downed the plane and confirmed that both sides were searching for the two missing airmen.
"Turkey will present its final stance after the incident has been fully brought to light and decisively take the necessary steps," said a statement from Erdogan's office.
Turkish newspapers were less restrained.
"They (the Syrians) will pay the price," said Vatan, while Hurriyet daily said "He (Assad) is playing with fire."
The joint Turkish-Syrian search and rescue operation sits uneasily with Turkey's hosting of the rebel Free Syrian Army fighting to topple Assad, once a personal friend of Erdogan.
The souring of relations over the past year has provoked concern among Turks that Syria may revive its former support for Kurdish Workers Party (PKK) insurgents in southeastern Turkey.
"It's possible the Turks were sending jets in the area in response to an apparent escalation of the PKK's activities," Hilal Khashan, political science professor at the American University of Beirut, told Reuters.
"Turkey may suspect that Syria and Iran are supporting Kurdish rebel activities now as a reaction to Turkish support of the Syrian revolt," he said.
However, Khashan said he did not expect a harsh military reaction from Turkey. "It is under a tight leash by the United States. They don't want to start a war tomorrow."