Declaring Syria an open threat to his country in the wake of attacks on a warplane, Turkey’s Prime Minister Recep Tayyip Erdogan told parliament Tuesday that if Syrian soldiers approached the border, such action should be viewed as a military provocation.

Separately, NATO has condemned Syria’s attack on the Turkish F-4 phantom plane, while expressing its support for alliance member Turkey.

Syria claimed it shot down the jet because it strayed into Syrian airspace.

The two pilots from the aircraft remain missing.