The Leon Dias vessel now under Benin navy surveillance

The navy of Benin is guarding a Greek-owned oil tanker hijacked by Nigerian militants who are holding five crew members hostage in Nigeria, a Nigerian agency that issues government statements and a shipping security expert said Wednesday.

The Liberian-flagged MT Leon Dias is anchored off Cotonou, Benin’s commercial capital, PR Nigeria agency reported.

It gave no other details and no news of the crew and hijackers.

The hijackers disembarked from the vessel on Sunday and took five hostages with them — the captain, chief engineer, third engineer, the electrician and a fitter, said Dirk Steffen, maritime security director of Denmark-based Risk Intelligence. The ship then sailed to Cotonou, he told The Associated Press.

Owner Leon Shipping and Trading in Athens did not answer requests for comment.

Earlier Nigerian officers said the vessel was hijacked Friday by separatists threatening to blow it up with its crew unless officials release Nnamdi Kanu, the director of the banned Radio Biafra who is accused of treason and terrorism.

Kanu’s detention since Oct. 17 has sparked violent protests and police are accused of killing several demonstrators.

The hijackers had indicated that separatists might be working with some Niger Delta oil militants recently accused of blowing up oil pipelines. But Steffen said the two groups from different tribes have different agendas and that the separatist claim likely is a cover to lend legitimacy to a kidnapping for ransom.

He said the Leon Dias had been attacked in April 2013 in the same area as the hijacking, about 115 miles (185 kilometres) southwest of Brass city, in the Bakassi Peninsula on the Atlantic Ocean coast that forms Nigeria’s southeastern border with Cameroon.

The Igbo people’s cause to create an independent state of Biafra in southeastern Nigerian sparked a civil war that killed a million people in the between 1967 and January 1970.