Somali pirates have released a German cargo vessel with 15 men on board, after owner of the ship paid a ransom amounting 750,000 dollars.

One Russian and four Ukrainians were among the freed crew, who suffering from poor health conditions after spending six months in captivity.

Marine expert Mikhail voitenko, who took part in the negotiations, said five pirates have left the vessel.

The vessel is believed to heading out of Somali waters to the open seas.