By JOE PARKINSON

ISTANBUL—Turkey on Saturday vowed to take "necessary steps" to respond to the downing of a Turkish military jet by Syria on Friday, but signals from Ankara and Damascus suggested neither wanted a military confrontation over the incident, which raised tensions along the neighbors' long border to an ominous new high.
The Turkish and Syrian navies on Saturday continued a joint search for the crew of the missing aircraft, an F-4 military jet, which Syria said fell into the Mediterranean Sea about six miles west of the Syrian village of Umm al-Tuyour. Turkish news networks reported Saturday evening that neither of the two pilots had been found.
Turkish President Abdullah Gul said on Saturday that Ankara couldn't ignore the incident and pledged that the government would do "whatever is necessary" once the facts became clear, Turkey's state-run Anatolian news agency reported.
Speaking to reporters in central Anatolian city of Kayseri, Mr. Gul didn't spell out what action Turkey might take, but he said the Turkish jet's action wasn't provocative, stressing that it was "routine" for jets to briefly cross into foreign airspace. A probe into the incident would look at whether in fact it was downed while in Turkish airspace, Mr. Gul said.
Syria has said the Turkish aircraft was flying low and well inside Syrian territorial waters when it was shot down, but a government official on Saturday appeared eager to defuse the crisis, telling a Turkish news channel that the downing of the jet was an accident, and not a hostile act against its neighbor.
Syrian Foreign Ministry spokesman Jihad Makdisi told the A Haber network that Syria had exerted its "sovereign right" against an "unknown" aircraft violating its air space.
Neighboring states and diplomats called for restraint, stressing that the incident underscored how the Syrian conflict had the capacity to spread across the region.
United Nations Secretary-General Ban Ki-moon urged Turkey and Syria to deal with matter through diplomatic channels.
During a news conference Saturday in Baghdad, Iraqi Foreign Minister Hoshyar Zebari said the news marked "a serious escalation," the Associated Press reported. "It is a security matter for Europe. It is a concern for the region and that is why we called for a calculated, well-drawn, democratic political transition. We do not want to see chaos in the region," he said. Other Turkish officials also called for restraint.
Deputy Prime Minister Bulent Arinc called for calm while the details of the incident remained unclear and stressed that the downed aircraft wasn't a warplane but an unarmed surveillance craft. "We should not give any credit to provocative acts of statements," Mr. Arinc said.
The incident underlined the heightened tensions in the region as Syria's revolt degenerates into an armed conflict that many analysts say could draw in neighboring states and perhaps prompt wider international military intervention.
The news also raised pressure on Turkey to take action against Syria after Ankara's increasingly harsh statements against the crackdown.
Foreign Minister Ahmet Davutoglu met Turkey's military commanders and intelligence chief to discuss Ankara's next steps and the search for the pilots. He was due to make a statement on Sunday morning.
Prime Minister Recep Tayyip Erdogan was scheduled to hold a second security meeting with senior officials later on Saturday, less than a day after he convened a crisis session on Friday evening.
Relations between Turkey and Syria, which share a 565-mile border, started to dissolve last year when Turkish officials began to criticize Syrian President Bashar al-Assad for refusing to end the crackdown against domestic opposition to his regime.
In April, when Turkey accused Syrian forces of firing at dissidents inside Turkey, Mr. Erdogan raised the prospect that Turkey, a member of the North Atlantic Treaty Organization, could call on the military alliance to protect Turkey's border against incursions by Syrian forces. The incident didn't prompt NATO military action.
How the downing of the jet plays out could depend in large part on Syria's response, analysts said. "If Syria assumes all responsibility and agrees to pay compensation, for example, this may affect" Turkey's reaction, Nihat Ali Ozcan, of Turkish TEPAV research institute, commented on NTV.
While Ankara has become one of the countries spearheading efforts to force Mr. Assad's ouster, it has been wary of being pressured to lead military action.
Turkish cabinet ministers have openly debated the idea of creating a buffer zone inside Syrian territory after thousands of refugees sought haven on Turkish territory. Turkey now hosts Syria's opposition Syrian National Council in Istanbul, and the leadership of the rebel Free Syrian Army in the southern province of Hatay.