BEIRUT — Turkey was weighing its response Saturday to the shooting-down by Syria of one of its planes over the Mediterranean, an incident that sent tensions soaring between two neighbors already at odds over the uprising in Syria.
The deliberations appeared to be focusing in part on the question of whether the Turkish plane was in Syrian airspace when it was hit Friday, as the Syrian government claims. Two pilots are missing, and Turkish and Syrian vessels are still looking for them.

Turkish President Abdullah Gul was quoted by Turkish media as saying that the government was trying to ascertain where the plane at the time, suggesting it was looking for ways to ease the crisis.
But Turkey, a NATO member, is not prepared to let the incident pass without response, Gul warned.
“It is not possible to cover over a thing like this,” the state news agency Anatolia quoted him as saying. “Whatever is necessary will be done.”
Turkish media initially reported that the plane was a U.S.-made F-4 fighter jet, but reports on Saturday said it was a reconnaissance aircraft.
According to Syria’s account of the incident, Syria’s air defenses opened fire with anti-aircraft artillery at what was described as “an unidentified aerial target [in] Syrian airspace coming from the west at a very low altitude and at high speed over territorial waters.”
The incident underscored the region’s jittery mood as the revolt in Syria degenerates into an armed conflict that many fear will spill beyond its borders, draw in its neighbors and perhaps prompt wider international military intervention.
Compounding the tensions, Turkey has emerged as the main conduit for the new supplies of weaponry that are flowing to Syrian rebels with funds from Saudi Arabia and Qatar and facilitated in part by the United States. More than 30,000 Syrian refugees have flooded into southern Turkey over the past year, and the leadership of the rebel Free Syrian Army is being housed at one of the refugee camps there.
It is not the first time Turkey has been ensnared in the violence since the uprising against President Bashar al-Assad’s rule erupted 15 months ago, souring the once-close relationship between Damascus and Ankara. After Syrian forces fired shots across the border into a camp for Syrian refugees in April, Turkey threatened to invoke a mutual-defense clause in the NATO charter.
Syria seemed eager to play down the plane incident. “There was no aggression,” Foreign Ministry spokesman Jihad Makdissi said on his Twitter account. “It was an unidentified target flying at very low range when it violated Syrian airspace.” He also emphasized the role that Syrian vessels were playing in helping search for the missing pilots.
The shooting nonetheless comes at a moment of heightened concern about the spiraling violence in Syria in the wake of the collapse of a U.N. peace plan brokered by special envoy Kofi Annan. The U.N. monitors who were dispatched to Syria to observe a now-nonexistent cease-fire have been confined to their hotels because it is too dangerous for them to go out, and the Security Council remains divided over what alternatives to pursue.
At a news conference in Geneva, Annan warned that unless the international community agrees on a way forward soon, “it will be too late to stop the crisis from spiraling out of control.”
Among the dozens of deaths reported in Syria on Friday were 25 men who had apparently been executed by rebel forces in a mass killing in the province of Aleppo, according to the Britain-based Syrian Observatory for Human Rights.A video posted on YouTube showed an array of blood-soaked bodies strewn beside a bullet-ridden pick-up on a deserted, unpaved rural road. Some were wearing military fatigues, others jeans and T-shirts. A voice identifies the dead men as “Assad’s shabiha,” a reference to pro-government militias that the opposition blames for much of the violence taking place.
Syria’s state news agency SANA also reported the killings, saying that “armed terrorists” had committed a “brutal massacre” in the Daret Azzeh area of Aleppo, one of several areas in the province that are slipping out of government control.
Special correspondent Suzan Haidamous contributed to this report.