Washington calls for postponement of Russian S-400 missiles delivery to Turkey

The United States has asked Turkey to postpone the delivery of S-400 missiles by Russia, sources said on Monday.
Washington opposes the purchase by Ankara of this missile system, which Moscow must deliver to Turkey in July.
A senior Turkish official, however, said the Turkish position had not changed: "We will buy the S-400 in July, our position has not changed."
The US administration last week asked Turkey to postpone this delivery, which could, she says, undermine Turkish participation in the F-35 fighter jet program. Discussions are continuing on this subject, the source added........