NATO will hold emergency talks Tuesday to discuss Syria's downing of a Turkish jet fighter, but the alliance is not expected to take military action, even if it confirms Turkey's claim that the unarmed plane was attacked in international airspace.
The incident has further raised regional tensions over the conflict in Syria, where some 40 people were reported killed Sunday in new clashes between rebels and government troops.
Sunday, U.S. Secretary of State Hillary Rodham Clinton sharply criticized Syria for downing the Turkish plane, which Turkey's Foreign Ministry called an "open and grave violation of international law" that would justify retaliation.
"The United States condemns this brazen and unacceptable act in the strongest possible terms," Clinton said in Washington. "It is yet another reflection of the Syrian authorities' callous disregard for international norms, human life, and peace and security."
Clinton said Washington will maintain close contact with Turkish officials as they determine their response, via the U.N. Security Council. "We will work with Turkey and other partners to hold the Assad regime accountable," she said.
Turkish state media reported Sunday that the RF-4E reconnaissance plane's wreckage was found in the Mediterranean Sea at a depth of 4,265 feet, but officials did not confirm the report. The two pilots remained missing.
Turkish Foreign Minister Ahmet Davutoglu said the jet was on a training flight to test Turkey's radar capabilities, not spying on Syria. He said the plane mistakenly strayed into Syrian airspace Friday but was quickly warned to leave by Turkish authorities and was a mile inside international airspace when it was shot down.
Syria insisted Saturday that the shooting was "not an attack" and that the aircraft had violated its airspace. But Turkish authorities say Syria didn't warn the Turkish plane or send its own jets to confront it.
At the request of Turkey, NATO's governing body will meet Tuesday to discuss the incident, said Oana Lungescu, a NATO spokeswoman. The consultations were called under Article 4 of NATO's founding Washington Treaty.
"Under Article 4, any ally can request consultations whenever, in the opinion of any of them, their territorial integrity, political independence or security is threatened," Lungescu said. The North Atlantic Council -- the ambassadors of the 28 NATO countries -- will decide whether to respond, she said.
Syrian activists reported violence in different parts of the country Sunday, saying nearly 40 people were killed.
The deadliest incident was in the northern town of Ariha, where a shell hit a home, killing seven members of the same family, the Britain-based Syrian Observatory for Human Rights said. A video posted online showed the seven men's bodies, some badly mutilated.