Turkey has deployed a large number of military vehicles to the Syrian border, the Turkish daily Milliyet reported on Tuesday.

According to the report, 15 armored tanks, long-distance guns and other military vehicles were deployed near the border. A report in the daily newspaper Hurriyet said military units increased security measures on the border following recent events that have strained the relations between the countries.

On Friday, Syria downed a Turkish jet in international airspace. Turkey said the jet was shot down without warning and without provocation.

On Tuesday, NATO firmly backed Turkey, saying Syria’s shooting down of the Turkish jet was “unacceptable.”

NATO’s Secretary General Anders Fogh Rasmussen condemned the incident, saying, “We consider this act to be unacceptable and condemn it in the strongest terms…It is another example of the Syrian authorities’ disregard for international norms, peace and security, and human life.”

Turkey has also filed a complaint with the UN against Syria over the downing of the jet.

Turkish Prime Minister Recep Tayyip Erdogan said on Tuesday that Turkey wasn’t seeking a conflict with Damascus, but stressed that Ankara’s cautious response to the incident shouldn’t be mistaken for weakness.

“We will not fall into the trap of warmongers, but we will not stay silent in the face of an attack made against our plane in international airspace,” Erdogan was quoted in a Wall Street Journal report as having told a meeting of his governing Justice and Development party in Ankara.

“Now the engagement rules by Turkish General Staff have changed….Every military element from Syria at the Turkish border that forms a security risk and danger, will be assessed as a threat and be treated as a military target,” Erdogan added.