(CNN) -- Turkey is changing its military rules of engagement and will now treat a military approach toward its borders from Syria as a potential threat that "will be dealt with accordingly," Turkish Prime Minister Recep Tayyip Erdogan said Tuesday.

The announcement is a significant escalation of rhetoric after Syria shot down a Turkish plane last week.

Erdogan criticized Syria harshly on Tuesday for shooting down the Turkish fighter jet, saying: "Even if the plane was in their airspace for a few seconds, that is no excuse to attack."

"It was clear that this plane was not an aggressive plane. Still it was shot down," Erdogan said.

The shooting down of the Phantom F-4 jet on Friday raised tensions between Turkey and Syria, two heavily armed regional powers.

NATO condemned it "in the strongest terms," Secretary General Anders Fogh Rasmussen said after the alliance met Tuesday at Turkey's request.