The Turkish National Security Council (MGK) reiterated on Wednesday Ankara’s condemnation of a Washington plan to set up a security border force in western Syria.
In a statement, the MGK said it would not allow the formation of a “terrorist army” along Turkish borders.
The US-led coalition in northern Syria said it was working with the mainly Kurdish YPG-led Syrian Democratic Forces (SDF) to set up a new 30,000-strong border force.
Turkey will respond immediately to any threats from Western Syria that could harm the country or its citizens, stressed the MGK.
It demanded that all weapons given to Kurdish fighters in Syria be collected without delay.
It also advised the cabinet of ministers to extend the emergency rule imposed shortly after a 2016 coup attempt.
Ankara has frequently expressed its opposition to Washington’s arming of Kurdish forces in Syria.
Turkish President Recep Tayyip Erdogan has said he will launch a military offensive in the coming days against territories controlled by Kurdish forces in northwestern and eastern Syria, and in particular the enclave of Afrin.
The US move to form the border force has been rejected by Tehran, Damascus and the Syrian opposition.
Turkish Foreign Minister Mevlut Cavusoglu said he told US Secretary of State Rex Tillerson that those plans were a "perilous" step that would "seriously endanger ties." The two met in Vancouver Tuesday.
"Such a development would damage Turkish-American ties in an irreversible manner," the state-run Anadolu Agency quoted Cavusoglu as saying on Wednesday.
Erdogan said the imminent military operation is to "purge terror" from near its borders. Along with Afrin, Erdogan has also threatened Manbij, a town the Kurdish-led SDF seized from ISIS in 2016.