Kjeld Fredriksen, duty commander at the Danish Admiral Fleet, said the ship was operated by CEC Clipper in Denmark, which has an ownership interest in the vessel. Choong said the ship flies a Bahamas flag.
Fredriksen said there were no Danes among the crew, which consisted of "Russians and Ukrainians as far as I know." He had no information on whether there were any casualties.
Choong said pirates are still attacking despite increased patrols and ships in the region being told to take extra precautions.
NATO has sent three ships to the Gulf of Aden - one of the world's busiest shipping lanes
- to help the U.S. Navy in anti-piracy patrols and to escort cargo vessels. The European Union has said at least four warships backed by aircraft will begin policing the dangerous waters in December. The EU flotilla will eventually take over patrolling the area from NATO ships.
Nevertheless, attacks have continued off Somalia, which is caught up in an Islamic insurgency and has had no functioning government since 1991.
There have been 81 attacks this year in the African waters, with 32 ships hijacked. Eleven vessels remain in the hands of pirates along with more than 200 crew, Choong said.
