ISTANBUL, Aug 4 (Reuters) - Three crew members were seriously injured after a roll-on/roll-off cargo ship was hit in a drone attack near Russia's Black Sea port of Novorossiysk, Turkey's maritime authority said late on Monday.

The Nadezhda was sailing from Novorossiysk to Turkey's northern Samsun port on Monday when it came under attack about 20 nautical miles off Novorossiysk, the maritime authority said in a statement.

All 22 crew members were evacuated to Russia including three seriously injured, it said, adding that the fire continued to burn in the bow of the cargo ship.

It was not immediately clear who was behind the strike on the ship.

(Reporting by Ezgi Erkoyun in Istanbul and Jekaterīna Golubkova in Tokyo; Editing by Tom Hogue)