But Washington has continued to offer support to its NATO ally Turkey, Reuters quoted Pompeo as saying at a press conference at the U.S. State Department.

The U.S. secretary of state gave no specific information on where or when the Turkish troops were killed.

Ankara and Moscow, who back opposing sides in the Syrian conflict, earlier this month reached a ceasefire in the country’s last rebel-held Idlib province following intense fighting between Turkish-backed rebels and Syrian forces supported by Russia.

The agreement followed the death of 36 Turkish troops in an air strike by Russian-backed Syrian government forces.