Pirates have kidnapped three sailors after they hijacked an oil tanker.
Six days ago 16 sailors on board the Monjasa Reformer ship rushed to a safe room as pirates flooded aboard, according to a spokesperson for the Danish shipping company.
The Monjasa, a chemical and oil tanker, was flying under the Liberian flag at the time of the attack.
After being hijacked on March 25, the crew sent out a distress call at 7.37pm local time - when 90 miles south of Bonny, Nigeria.
Then, late last night, the ship was located by the French Navy, who had been looking along with British naval forces, and safely secured in the Gulf of Guinea.
But of the 16 crew members, three seafarers who had been on board have disappeared.
The company said the pirates had "abandoned” the vessel but taken some of the crew with them.
The rescued crew members are in good health, the company said, but the location of the missing sailors isn't known.
They added: "Our thoughts are with the crew members still missing and their families during this stressful period.
"Monjasa will continue working closely with the local authorities to support our seafarers safe return to their families.
"At the same time, Monjasa would like to express our sincere thanks to the French Navy and all other parties who provided their assistance so far.”
It is understood there was no damage to the ship, and during the desperate hunt for the missing crew, it was spotted on March 28, 470 nautical miles from where it first went missing.
The 4,200 square-mile Gulf of Guinea, west of Africa - which stretches from Angola to Senegal - is known to be one of the world's most-dangerous shipping routes.
Thanks to collaborations between naval authorities rolled out in 2021, piracy cases have been on the decline, the UN Security Council states.
The number of attacks has reportedly dropped significantly leading up to 2022, when 19 attacks were reported with 35 reported in 2021 and 84 in 2020.
At the time of the attack on the ship, it had been sitting idle and in response the crew secured themselves inside the “citadel” in accordance with anti-piracy protocol.
The Monjasa Reformer is used in West Africa as part of the company’s global fuels operations and was carrying gas oil, very low sulphur fuel oil and high sulphur fuel oil products on board.
The Danish group previously said that the safety and well-being of crews and contractors was its top priority, not least in West Africa where piracy is a known risk factor.
