
The Irene SL, the length of three soccer pitches and with 25 crew members on board, was carrying about 2 million barrels of oil, or nearly one fifth of daily US crude imports.
The hijacking came a day after an Italian tanker carrying oil worth more than US$60 million was snatched by Somali pirates, reinforcing industry fears that the piracy scourge is "spinning out of control".
"This morning the vessel was attacked by armed men," the Irene SL's Greece-based manager Enesel said. "For the moment there is no communication with the vessel."