NAIROBI, June 22 (Xinhua) -- A maritime official from Kenya said on Thursday that a cargo ship carrying 20,000 tons of coal sank off the coast of Somalia, and a rescue mission was under way to save the crew.

    Andrew Mwangura, coordinator of Seafarers Assistant Program, said in a statement that the MV Kanaya sank on Tuesday, but 18 crew members were plucked from the vessel and are currently believed to be floating on life rafts.

    "There are 18-19 crew members in life rafts. Two vessels (M/V Mearsk Arkansas and M/V Jo Betula) are en route and they are already there for rescue mission," Mwangura said.

    "The crew sent out a distress signal before they abandoned the ship," Mwangura added.

    However, Mwangura could not confirm whether the sinking ship was due to piracy, which has been a growing problem off Somalia's 2,500 km coastline -- the longest in Africa.

    It was the latest in a series of incidents off the coast of Somalia.

    On March 18, two U.S. navy ships exchanged gunfire with suspected pirates, killing one and wounding five. No U.S. sailors were injured.

    Somalis involved in that incident later claimed they were patrolling Somali waters to stop illegal fishing when the U.S. ships fired on them.

    Somalia has had no coast guard or navy since 1991, when warlords ousted the ruling dictator then turned on each other. Enditem