Somali pirates have hijacked a German cargo ship called the Beluga Nomination, the ship's operators said on Tuesday.

A spokeswoman for Bremen-based Beluga Shipping did not give details regarding the ship's crew, country of registration or location. Arabic language media have reported the ship was hijacked off the Somali coast on Monday.

"The MV Beluga Nomination has been attacked and hijacked by Somali pirates," the spokeswoman said.

Ukrainian media reports, citing the country's foreign ministry, said several Ukrainians were on board as crew members, along with nationals of Russia, the Philippines and Poland.

Somali pirates are making tens of millions of dollars in ransoms from seizing ships, including tankers and dry bulkers, in the Indian Ocean and the Gulf of Aden, despite the efforts of foreign navies to clamp down on such attacks.

A report this month said piracy worldwide was costing the global economy $7-12 billion a year, with Somali sea-bandits in particular driving up the cost of shipping through the Indian Ocean.-Reuters