Somali pirates hijacked a tanker managed by an Indian firm with 21 Indian sailors on board on Saturday while it was being loaded at a port in the Gulf state of Oman, India's government shipping agency and a Gulf shipping source said.

The Directorate General of Shipping said the M V Fairchem Bogey, an chemical-oil tanker managed by Mumbai-based Anglo-Eastern Ship Management, was hijacked while anchored in  Salalah port. It gave no further details.

A Salalah-based shipping source said the vessel was about to be loaded with methanol when it was hijacked early in the morning.

"The ship has been hijacked by Somali pirates from Salalah port and might already be on the way to Somalia," the source in Salalah told Reuters. "The ship was at Salalah anchorage since yesterday evening."

There was no immediate comment from Salalah port.

Oman lies at the mouth of the Gulf, a strategic, heavily patrolled waterway which channels a bulk of the world's crude shipments.

Somali pirates behind similar vessel hijackings usually operate in Indian Ocean waters, but in January, a 20,586-tonne Algerian-flagged bulk carrier was seized about 150 miles southeast of Salalah. 

The ship, with 27 crew from Algeria, Ukraine and the Philippines, was heading to Dar es Salaam, Tanzania, from Salalah with a cargo of clinker. – Reuters