BRUSSELS — As the crisis in Syria threatened to spill beyond its borders, Turkey sought support on Tuesday from its partners in the NATO alliance at an emergency meeting of envoys in Brussels called after Syria shot down a Turkish warplane over the Mediterranean Sea.
While Syria maintains the plane was brought down well within its airspace, Turkey says the two-seat F-4 fighter plane was attacked over international waters after straying briefly into Syrian space.
Turkish Foreign Minister Ahmet Davutoglu has told state-owned TRT television that the aircraft was struck by Syrian antiaircraft fire outside of Syrian airspace. "Our plane was hit in international airspace, 13 nautical miles out of Syria, when Syrian territorial space is 12 miles," he said.
But the Syrian Foreign Ministry said on Monday that the airplane was brought down by an antiaircraft weapon with a range of less than two miles.
The two crewmen are still missing after the incident last Friday. News reports said NATO ambassadors would likely condemn the downing of the Turkish jet without ordering measures, such as military action, that would inflame the crisis and turn it into a r broader conflict.
Western defense analysts said the incident had shown that, unlike the example of Libya last year, when NATO planes enforced a no-fly zone as rebels pressed for the ouster of Col. Muammar el-Qaddafi, the Syrian military could likely offer much stiffer resistance.
"After its experience in Libya, NATO certainly does not want to get into another air war with the Syrians, who are in much better shape than the Libyans were to conduct one," said Michael Corgan, a specialist in international security issues at Boston University.
In calling for the meeting in Brussels on Tuesday, Turkey said it will invoke Article 4 of the NATO treaty, which provides for consultations by the allies when one of them is attacked or threatened, rather than the much stronger Article 5, in which an attack on one member is considered an attack on all NATO countries.
The episode risks drawing in Russia, Syria's principal weapons supplier and international champion, which has signaled concern about the NATO meeting. SANA, Syria's state news agency, quoted Russian Deputy Foreign Minister Alexander Grushko as saying he hopes NATO will not take measures on Tuesday "that would aggravate situation in Syria" or prevent a political settlement there.
Russia, with Chinese support, has shielded President Bashar al-Assad against the efforts of Western and some Arab nations to press for a settlement that would remove the Syrian leader from office as part of a transition.
The nature of the weapons system that brought down the Turkish plane has not been clearly established. A senior Syrian official said it was a type of machine gun.
Less than two weeks ago, by apparent coincidence, Russia's main arms exporter said it was supplying Syria with defensive missile systems that could bring down airplanes or sink ships.
"I would like to say these mechanisms are really a good means of defense, a reliable defense against attacks from the air or sea,'' Anatoly P. Isaykin, the general director of the company, Rosoboronexport, said Friday in an interview. ''This is not a threat, but whoever is planning an attack should think about this.''
On Monday, Jihad Makdissi, the Syrian Foreign Ministry spokesman, said the wreckage of the plane "shows holes in the tail-end of the plane which confirm that it was shot down by a ground-based machine gun, not missiles."
"Had the aircraft been over territorial waters, we would have used missiles, not a land-based antiaircraft machine gun with a maximum range of 2.5 kilometers," he said. "All of this confirms the falsity of the allegations that the aircraft was shot down outside Syrian territorial waters."