A South Korean cargo ship with 21 crew was hijacked in the Indian Ocean, the Yonhap news agency reported Saturday citing a foreign ministry official in Seoul. The 10,000-ton ship carrying chemicals was apparently hijacked by Somali pirates, the report said. The vessel belonged to Samho Shipping, based in the southern port city of Busan, and had eight South Koreans, two Indonesians and 11 others from Myanmar on board. According to dpa, the freighter was sailing from the United Arab Emirates towards Sri Lanka when it was hijacked in the waters between Oman and India, Yonhap reported. Its current location is unknown, the official said. The European Union's anti-piracy mission, EU NAVFOR, said that as of January 1, 28 ships and 672 hostages are being held by Somali pirates. Somali pirates have driven up shipping costs in the Indian Ocean, resulting in world economic losses estimated at 7-12 billion dollars a year, a study by US think tank One Earth Future Foundation said Thursday. Armed with AK-47s, pirates in rickety skiffs have carried out brazen hijackings, seizing massive oil tankers, cargo vessels and luxury boats. Navies from the United States, EU countries, China, India, Russia and Japan have been deployed in joint efforts to fight piracy, adding expenses to their national defence budgets.