The US has urged Turkey on Friday not to buy more Russian S-400 air defence systems, warning of further risks if the purchase goes ahead, US Deputy Secretary of State Wendy Sherman told journalists.
"We have urged Turkey at every level and opportunity not to retain the S-400 system and refrain from purchasing any additional Russian military equipment," Sherman responded when asked about Turkish President Recep Tayyip Erdogan's visit to Russia.
The US official added:
We continue to make that clear to Turkey and what the consequences will be if they move in that direction.
Last week, Erdogan met with Russian counterpart Vladimir Putin and discussed greater military cooperation, including warplanes and potentially submarines.
Meanwhile, Sherman stressed that the US values its relationship with Turkey, pointing to its welcoming of millions of Syrian refugees and offers to help restore Kabul International Airport.
"Turkey is a challenge sometimes. I am sure they find the United States a challenge at times. But they are a valued NATO ally," Sherman affirmed.