Turkey has requested that NATO consider the attack on one of their planes by Syria as an attack on the entire NATO alliance, which could lead to a major regional escalation.

Syria downed the Turkish jet late last week, and while the Syrians reportedly apologized for their actions, today they reacted by denying that they knew the jet was Turkish. The two crew members from the first plane have not been found. Turkey believes that the plane briefly crossed into Syrian airspace, but quickly realized the mistake and moved back. It is not known whether the jet was shot down over Syria or Turkey. It was also revealed today by deputy prime minister Bulent Arinc that Syria fired on a second Turkish plane, a search-and-rescue vehicle that was attempting to find the first downed plane.

The incident led to Turkey calling for an emergency NATO meeting to discuss possible responses. But even though Arinc and most Turkish leaders have said they do not intend to go to war with Syria, and even though it is not expected that NATO will press for military action over the incident, the push to view the attack as a collective security issue should raise concerns.

Turkey will push NATO to consider the armed attack under Article 5 in a key alliance treaty, Arinc said. Article 5 states that an attack against one NATO member shall be considered an attack against all members.

The North Atlantic Council — which includes ambassadors of the 28 NATO countries — works by consensus and all members must approve any action. The meeting Tuesday comes after Turkey requested it under Article 4 of the treaty, which allows a NATO ally to request such a consultation if it feels its territorial integrity or security has been threatened.

Asked if Turkey will insist on the activation of Article 5 of NATO, Arinc said, “No doubt, Turkey has made necessary applications regarding Article 4 and Article 5.”

This is the second time that Turkey has threatened to invoke Article 5 against Syria. The first time came when Turkish nationals were killed by Syrian government forces in a cross-border skirmish. Most people are extremely sanguine that this will not spill over into a military escalation. Indeed, the first hint of Article 5 did not, either. The UN Security Council or the Arab League would be unlikely to bless such a measure, for example.

However, today a Syrian general and 33 soldiers defected into Turkey. This follows a report of an air force pilot going AWOL into Syria. You can see the Assad government pointing the finger at Turkey for somehow encouraging these defections. And obviously the sharing of a border has led to complications. NATO requirements are not ambiguous on this point. Article 5 stipulates that an attack on Turkey really is seen as an attack on the entire alliance. I wouldn’t be so sure about this gradually escalating, and rhetorically speaking, it already has.