U.S. officials have floated the suggestion over the past month with their Turkish counterparts but no specific or formal request was made, the sources told Reuters. They said it also came up briefly during Deputy Secretary of State Wendy Sherman's visit to Turkey earlier this month.
The Biden administration has been asking allies who have been using Russian made equipment and systems including S-300s and S-400s to consider transferring them to Ukraine.
The idea, which analysts said was sure to be shot down by Turkey, was part of a wider discussion between Sherman and Turkish officials about how the United States and its allies can do more to support Ukraine and on how to improve bilateral ties.
The Turkish authorities have not commented on any U.S. suggestion or proposal relating to the transfer to Ukraine of Ankara's S-400 systems, which have been a point of long-standing contention between the two NATO allies.
Turkish foreign ministry officials were not immediately available for comment.
