Turkey's Russian missile buy 'disappointing': Pentagon nominee

President Donald Trump's nominee to lead the Defence Department called Turkey's acquisition of a Russian missile defense system "disappointing" Tuesday, in the administration's first comment since the first S-400 missile parts were delivered last week.

"It's certainly disappointing," Defence Secretary nominee Mark Esper told his Senate confirmation hearing.

"Turkey has been a long-standing and very capable NATO ally, but their decision on the S-400 is the wrong one and it's disappointing," he said.

Esper said he would abide by the decision last year to drop Turkey from NATO's F-35 fighter jet development programme due to Ankara's decision to buy the S-400 system, the delivery of which began on Friday.

Esper said he had already told Turkish Defense Minister Hulusi Akar that his policy is, "You can either have the S-400 or the F-35. You cannot have both."