Mark Esoper, US Defense Secretary said on Monday that he wanted an explanation from Ankara over threats to close two strategic military bases used by the US in Turkey.

On Sunday, while speaking to a pro-government television channel Turkey’s president Recep Tayyip Erdogan threatened to close the Incirlik and Kurecik bases used by the US. The two bases sit on Turkey’s southwest cost, near Syria’s border.

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While talking to media, Esper told the reporters that he would need to speak to his counterpart, defense minister Hulusi Akar to understand what Turkey really mean and how serious they are?

“If the Turks are serious about this, I mean, they are a sovereign nation to begin with… they have the inherent right to house or not to house NATO bases or foreign troops,” Esper.

“I think this becomes an Alliance’s matter, their commitment to the Alliance, if indeed they are serious about what they are saying,” he added.

It was also noted that Esper was disappointed by the direction Ankara seem to be taking, moving NATO away and getting closer to Russia.

According to details, Turkey faces US sanction from the US for buying Russian S-400 missile defense system.