The tanker, which was hijacked together with its crew off the Nigerian coast, was released yesterday morning, the piracy watchdog said.
Armed pirates, mainly operating in the country's oil rich southern delta region, boarded the cargo ship MT Halifax near Port Harcourt, the capital of Rivers State, officials had said.
The website of the Greece-based ship owners, Ancora Investment Trust Inc, had said that Indians, part of the crew, were two in number.
In July, a Greek oil tanker was hijacked by pirates along with its 20 crew members off the coast of Benin. The ship 'Aegean Star', which was later released, belonged to Endeavour Marine Agency based in Greece's main port of Piraeus.