NAIROBI: Pirates have hijacked a Greek-owned oil tanker carrying 135,000 metric tonnes of crude oil while in the Arabian Sea off Oman, the vessel's manager said.

Dynacom Tankers Management said it had lost contact with the crew of the MT Smyrni following the attack at 1115 GMT on Thursday.

“The Liberian-flagged Tanker, the M/T SMYRNI, is carrying a cargo of 135000 MT of crude oil,” it said.

Dynacom gave no further details but a Kenya-based piracy expert said the vessel was headed for the Somali coastline.

Industry websites said the vessel had sailed from Turkey, but there were mixed reports about its destination.

OceanUSlive.Org, a social networking site for the maritime industry, said the attack was one of four to have taken place in the Arabian Sea in the past few days after a lull in pirate activity.

Seaborne gangs are making tens of millions of dollars in ransoms, and despite successful efforts to quell attacks in the Gulf of Aden, international navies have struggled to contain piracy in the Indian Ocean and Arabian Sea owing to the vast distances involved.