Dubai-based Vela International Marine says company response teams have been established and are working to ensure the release of the crew and the vessel.
The US Navy said the MV Sirius Star was seized off the coast of Kenya on Saturday and that the bandits were taking the ship to a Somali port known as a hub of pirate activity.
A statement posted on Vela's website late on Monday says the ship was hijacked on Sunday. The discrepancy could not immediately be explained.
Attacks by Somali pirates have surged this year. The Saudi tanker was the largest ship taken. -- AP