ANKARA (Reuters) - Turkish Foreign Minister Hakan Fidan will visit Ukraine on Friday, according to Turkish diplomatic sources quoted by the state news agency Anadolu.

Turkish officials have repeatedly expressed interest in a mediation role between Russia and Ukraine to re-initiate the Black Sea grain deal.

Russia has blockaded Ukrainian ports since it invaded its neighbour in February 2022, and threatened to treat all vessels as potential military targets after pulling out of a U.N.-backed safe-passage deal for Black Sea grain exports last month.

The visit would come a week after Ukraine announced a "humanitarian corridor" in the Black Sea to release cargo ships that have been trapped in its ports after the termination of the main deal.

(Reporting by Ece Toksabay; Editing by Alison Williams)