Twenty three Indian sailors were on board the oil tanker operated by the Dubai-based company, Pioneer Ship Management Services LLC. Pat Adamson, the company's spokesperson, told PTI that all the crew on the tanker are Indians.
"There was a call from one of the crew members to the management company saying the vessel was boarded by pirates but nobody was harmed," he said.
"Pirates have not yet established contact with the company," Adamsan said, adding "we have not got any report of loot so far."
"We understand that a naval ship is on the way to intercept the vessel," he said. Earlier, IMB said the Nigerian authorities had been notified of the attack and were taking action.
It said the sailors had locked themselves in a safe room to avoid harm by the attackers who are suspected to be oil thieves from Nigeria's Niger Delta region.
Last month, pirates had hijacked and looted two oil tankers off nearby Togo. The ships and all crew members were later freed.
Also, an oil vessel was seized last week by pirates, off the Coast of Togolese capital of Lome and released few days later near Nigeria with its 23 Russian crew members. About 3,000 tonnes of fuel was stolen from the ship. The Gulf of Guinea has witnessed 37 attacks on ships this year alone.