By a vote of 320-129, members of the Turkish Parliament voted to allow military retaliation against a Syrian mortar strike across the border Wednesday that left five Turkish civilians dead.
Turkish Prime Minister Recep Tayyip Ergodan signed the measure that states the ongoing crisis in Syria is a threat to national security.
Turkish Deputy Prime Minister Besir Atalay was quoted by Turkish newspaper Today's Zaman as saying the measure wasn't a declaration of war.
"This is not a motion for war but a measure for deterrence," he said.
NATO, in a statement, said it stood by Turkey as a member state. The "aggressive acts" by the Syrian military, the alliance said, was a flagrant breach of international law that represented a "clear-and-present" danger to an allied state.
U.N. Secretary-General Ban Ki-moon expressed concern about the escalation of the Syrian conflict.
"The secretary-general has repeatedly warned that the ongoing militarization of the conflict in Syria is leading to tragic results for the Syrian people," a statement from Ban's spokesman read.
Ankara has received no response from Damascus over the border incident.