Turkey’s President Recep Tayyip Erdogan on Sunday threatened to close two strategic military bases used by the United States in Turkey, after Washington warned of sanctions over Ankara buying Russian arms.

“If necessary, we can close Incirlik and we can close Kurecik,” Erdogan on the pro-government A Haber television channel. The two bases sit on Turkey’s southwest coast, near the border with Syria.

Erdogan has regularly raised this possibility in the past, at times of tension between the two countries.

The US airforce uses the airbase at Incirlik for raids on positions held by the so-called Islamic State group in Syria. The Kurecik base houses a major NATO radar station.

Foreign Minister Mevlut Cavusoglu raised the issue of the bases last week. Responding to the US threat of fresh sanctions, he warned that their closure could be “put on the table”.

Turkey faces US sanctions over its decision to buy the Russian S-400 missile defence system, despite warnings from Washington.

And on Friday, Turkey summoned the US ambassador after the US Senate followed the lower house and voted to recognise the 1915 killings of Armenians as genocide. The bill has yet to be signed by President Donald Trump.

Armenia claims 1.5 million died in the killings. Turkey says the number of deaths was far lower and Turks also died, blaming the killings on the First World War.