U.S. intelligence indicates that a Turkish warplane shot down by Syrian forces was most likely hit by shore-based antiaircraft guns while it was inside Syrian airspace, American officials said, a finding in tune with Syria's account and at odds with Turkey.
The Turkish government, which moved tanks to the Syrian border after the June 22 incident, says the debris fell in Syrian waters, but maintains its fighter was shot down without warning in international airspace. Ankara also has said the jet was hit too far from Syrian territory to have been engaged by an antiaircraft gun.
Damascus has said it shot down the plane with an antiaircraft battery with an effective range of about 1.5 miles.
"We see no indication that it was shot down by a surface-to-air missile" as Turkey says, said a senior defense official
. Officials declined to specify the sources of their information. The senior U.S. defense official cautioned that much remains unknown about the incident.
A Turkish official said he wasn't aware of the American doubts, and reiterated the government's position that a Syrian missile downed the plane in international airspace.
The Turkish government has scheduled a special meeting for Saturday morning on Syria. A spokesman for the prime minister said the U.S. intelligence on the incident would likely be discussed.
The downing of the jet spurred fears of a widening regional conflict and led the North Atlantic Treaty Organization, following a presentation on Tuesday by Turkey, to condemn Syria's action.
The use of antiaircraft fire would suggest the Turkish plane was flying low to the ground, and slowly, U.S. officials said—though Syria said the jet was traveling at 480 miles an hour.
If hit by antiaircraft fire, the jet likely came closer to the Syrian shoreline than Turkey says, U.S. officials said
The plane's pilots haven't been found, and the Turkish Navy has continued to search for them. U.S. officials say they believe the pilots perished.
Some current and former American officials believe Ankara has been testing Syrian defenses. The version of the Turkish F-4 Phantom that was shot down typically carries surveillance equipment, according to U.S. defense officials.
A former senior U.S. official who worked closely with Turkey said he believed the flight's course was meant to test Syria's response. "You think that the airplane was there by mistake?" the former official said.
"These countries are all testing how fast they get picked up and how fast someone responds," said a senior U.S. official. "It's part of training."
The Turkish official said the plane wasn't on a surveillance mission. "All NATO members have condemned the Syrian hostile act and have supported Turkey," the official said.
The emerging discrepancies could prove embarrassing to Ankara and strain continuing discussions between the U.S. and Turkey
, a NATO ally that shares a long border with Syria.
Turkey occupies a critical role in the U.S. and Western strategy for dealing with the Syrian crisis. American officials and defense analysts say the U.S. approach depends largely on Turkey's willingness to keep pressure on Syrian President Bashar al-Assad.
NATO officials said Turkey's presentation on the incident on Tuesday was very detailed, but diplomats didn't closely question the Turks on their version of events. The U.S. backed Turkey and, American officials said, pushed NATO to issue a statement sharply condemning Syria.
The incident has put NATO in a tough spot. Alliance members are eager to back Ankara, but don't want to be dragged into a military conflict in Syria.
If the plane had been struck by a missile, a senior military official said, it would be an indication that Damascus had authorized the action. But the use of antiaircraft fire may mean a local commander decided on his own initiative to fire at the Turkish plane, according to officials and analysts.
U.S. defense officials said they weren't alarmed by Turkey's movement of forces to its border with Syria. Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, praised Turkey's "very measured" approach. "I've asked them, and they are not seeking to be provocative," Gen. Dempsey said.
The U.S.-Turkish relationship is unlikely to be affected by the apparent discrepancies in accounts of the downing of the jet. Cooperation between Ankara and Washington has grown closer in recent months, after a period of significant strain in 2009 and 2010.