US Secretary of Defense Mark Esper cannot say how seriously the Turkish authorities are set to close the Incirlik airbase for the US military, Reuters reported.

“It has not been brought up to me before. The first I heard of it was reading it in the papers as you just mentioned and so I need to talk to my defense counterpart to understand what they really mean and how serious they are,” Esper told reporters.

According to him, if Ankara is seriously talking about closing the base for the United States, then this issue should be discussed with NATO.

“They are a sovereign nation to begin with, so they have that inherent right to house or to not house NATO bases or foreign troops,” Esper said.  “But again, I think this becomes an alliance matter, your commitment to the alliance, if indeed they are serious about what they are saying.”

Turkish President Recep Tayyip Erdogan confirmed Sunday that his country could close Incirlik airbase to the US if Washington decides to impose sanctions on Ankara. Turkish FM Mevlut Cavusoglu on December 11 also spoke about Ankara’s readiness to consider closing the Incirlik base for US troops if the US imposes sanctions on the acquisition of Russian S-400 anti-aircraft missile systems.

Meanwhile, the Pentagon, commenting on the Turkish president's statement, said earlier that the US uses Turkish military bases, including Incirlik airbase, only with the permission of Ankara.

This is not the first time Turkey has talked about the possibility of closing the Incirlik airbase for the US military. Usually, such rhetoric of Ankara arises in the light of threats from Washington, but it has not yet reached any concrete steps in this direction.