The Estonian-owned cargo ship Helt has sunk off the Ukrainian port of Odessa after an explosion, the vessel's manager says.
Two crew members were in a life raft at sea while four others were unaccounted for, Igor Ilves, managing director of Tallinn-based manager Vista Shipping Agency, told Reuters.
"The vessel has finally sunk," he said.
"Two of the crew are in a raft on the water and four others are missing. I don't know where they are at the moment."
Ilves said the vessel might have struck a mine.