Russian Foreign Ministry said Thursday that hijackers have released 23 Russian citizens onboard a Greek-owned oil tanker in Togolese waters.

"All of the crew, including 23 Russians, are safe now. The tanker will continue its voyage," said the ministry in a statement. The statement failed to say when the crew members were released.

The Russian crew and the Greek captain were released by the pirates who pumped out 3,000 tonnes of petrol before leaving, the crew company said.

Nobody on the tanker got injured during the hijack. The crew members were assessing the damage of the ship before repairing it, according to head of the crew company Oleg Kravchenko.

The Greek-owned oil tanker with 24 crew members aboard was seized only miles off the Togolese capital Lome on Tuesday morning.

The ship owner got in touch with the captain shortly after the attack and learned the crew members' lives were not in danger, the ministry said.

Togo's coast guard boats chased the seized tanker but failed to catch it, the ministry said earlier, adding preliminary information showed the ship was in international waters far from Nigeria after the attack.

It was at least the second major attack by pirates in less than two weeks in the oil-rich Gulf of Guinea, running from Guinea on Africa's northwestern tip to Angola in the south.