A chemical tanker with 21 crew members has been hijacked by Somali pirates near Madagascar, the Norwegian owner said Saturday.

It was not clear whether anyone in the crew, all from Myanmar, had been injured in the attack early Friday or whether any ransom had been demanded.

Svenn Pedersen, CEO and managing director of Norway's Th. Broevigtank Shipowners, said the UBT Ocean chemical tanker was on its way from the United Arab Emirates to Tanzania when it was hijacked about 300 miles from its destination.

"The captain made contact saying pirates were on board and then the contact was cut off. Nothing has been heard from the ship since then," Pedersen said.

He said the 9,000-ton vessel is registered in the Marshall Islands and was carrying fuel oil.

Edward Ion, a spokesman for the vessel's technical manager, Ship Management Associates in Singapore, said attempts have been made to re-establish contact with the vessel, but it has so far been unsuccessful.

"We're making every effort," he said, adding the company is cooperating with local authorities and monitoring agencies and anti-piracy forces in the region. "Obviously we're very concerned about this."

The hijacking is one of the southernmost attacks the pirates have ever launched, and serves as yet another indicator that increased naval patrols in the Gulf of Aden are pushing the pirates' range further south and east into the Indian Ocean.

Duncan Findlay, an official with Ship Management Associates, said the ship complied with industry guidelines because it was registered with, and reported to, the UK Maritime Trade Operations, a group that oversees the route the vessel was taking.

According to the company, the vessel was not registered with the EU Naval Force-run Maritime Security Centre for the Horn of Africa because the ship would not go near the Horn of Africa.

"It would have been the incorrect coordination center because the ship was 1,000 nautical miles south of the Horn of Africa," Ion said.

On Friday, a French frigate involved in an EU anti-piracy mission off Somalia detained 22 suspected pirates from six separate boats in the Indian Ocean. According to the French Defense MInistry, the suspects are being held on the frigate.