NATO allies will express political support for Turkey on Tuesday at an emergency meeting to discuss the shooting down of a Turkish military jet by Syria last week, but will likely stop short of assessing prospects for military involvement.

Ankara requested a meeting of NATO's North Atlantic Council to discuss the incident, which it has branded an "act of aggression". Damascus said it shot the aircraft down in self-defence after it strayed into Syrian airspace.   

The meeting is only the second time in NATO's 63-year history that member countries have convened under Article 4 of its charter, which provides for consultations when a member state feels its territorial integrity, political independence or security is under threat.

"We may get a statement of solidiarity with Turkey," a NATO official said.
Secretary-General Anders Fogh Rasmussen was to make a statement around 11:30 a.m. (09:30 GMT) after the talks among NATO ambassadors at alliance headquarters in Brussels.

Analysts said Rasmussen's message was likely to be measured, reflecting Western reluctance to commit to any military action or anything that could trigger a regional sectarian war.

"There is very little appetite from the alliance to undertake what we call a discretionary war," said Clara Marina O'Donnell, a fellow at the Brookings Institution in Washington.

Turkey's choice to seek consultation under Article 4, instead of asking for military help under the organisation's collective defence provisions, known as Article 5, suggested Ankara was hoping to steer clear of inflaming the conflict.

"This is a signal from Turkey that they are not too keen to go down the military route at this stage. They are trying to de-escalate the situation," she said.

Turkey rejected assertions from Damascus that its forces had no option but to fire on the F-4 jet as it flew over Syrian waters close to the coast on Friday.

In a letter to the UN Security Council, Turkey condemned a "hostile act by the Syrian authorities against Turkey's national security", saying it posed "a serious threat to peace and security in the region".

Syria warned Turkey and NATO against retaliation. EU foreign ministers on Monday urged Turkey to show restraint, saying they would increase pressure on Assad.

The only other time NATO has convened under Article 4 was in 2003 to discuss the Iraq war, again at the request of Turkey.

The unarmed reconnaissance jet had briefly entered Syrian airspace as it approached land after patrolling the eastern Mediterranean, Turkish Deputy Prime Minister Bulent Arinc said, but was warned by Turkish radar controllers and immediately left and turned again out to sea.

It then made another approach to land when it was shot down 13 miles off the coast in international airspace, he said, out of the reach of Syria's anti-aircraft guns.

"According to the data in our hands, it points to our plane being shot by a laser or heat-guided surface-to-air missile. The fact our plane was not given an early radar warning, suggests it was not a radar-guided missile," said Arinc.

Turkey had drawn close to Syria before the uprising against President Bashar al-Assad 15 months ago but turned against him when he responded violently to pro-democracy protests inspired by popular upheavals elsewhere in the Arab world.

Turkey shelters the rebel Free Syria Army (FSA) and hosts 32,000 Syrian refugees on its southeastern border with Syria, some 50 km (30 miles) from where the Turkish aircraft was shot down. But it denies providing arms for the insurgents.