The Assad regime has massed approximately 170 tanks near the Turkish border, according to an unconfirmed report on Friday by a general in the Free Syrian Army.

General Mustafa al-Sheikh told Reuters that the tanks are now located 30 kilometers (19 miles) from the border, northeast of Aleppo.

“They either want to move toward the border to confront Turkish troops stationed there, or they are planning to attack rebels in towns near the border,” al-Sheikh said.

The move comes after Turkey on Thursday sent anti-aircraft guns, rocket launchers and other fortifications to its frontier with Syria, marking an escalation in hostilities between the two countries.

Last week, Assad’s forces shot down a Turkish F-4 jet which they claimed had made an illegal foray into Syrian airspace. The Syrian government later claimed that the plane may have been shot down because it was mistaken for being Israeli.