US Defense Secretary Mark Esper said on Monday he needed to speak with his Turkish counterpart to understand how serious President Recep Tayyip Erdogan was when he said he could shut down the Incirlik air base, which hosts US nuclear warheads.
"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.