Turkey has mobilized and deployed tanks and missile batteries on the Syrian border adjacent to a Kurdish region that declared autonomy from Damascus, the Turkish Cihan News Agency reported on Thursday.

Trucks loaded with battle tanks and missile batteries departed from the southern Turkish town of Sanlıurfa, bound for the Mursitpınar border crossing, the report said.

The border towns of Amuda, Derik, Kobani (aka- Ayn al-Arab) and Afrin were reportedly under the control of a Kurdish group called the Democratic Union Party, allegedly affiliated with the PKK.

The mobilization of Turkish troops toward the border came a day after Turkish Prime Minister Recep Tayyip Erdoğan warned that Kurdish control over western Syria could prompt Turkey to invade.

“If there are formations that are being set up right now that [result in] a terrorist act, then it is our most natural right to intervene,” Erdoğan said.

The presence of Kurdish groups affiliated with the PKK could provide Turkey with a casus belli in Syria, analysts believe. The PKK, a Kurdish group designated by the US, the EU, and Turkey as a terrorist organization, has waged a decades-long conflict against Ankara.

Erdoğan’s rhetoric regarding Syria has grown increasingly belligerent since the uprising there broke out 16 months ago. Last month, Syria shot down a Turkish Air Force jet, which nearly prompted military retaliation by Turkey.

Ankara warned Syria earlier this week that any cross-border violence would be repaid in turn.