The product tanker Monjasa Reformer "experienced an emergency situation" on Saturday around 260 kilometres west of Port Pointe-Noire in the Republic of Congo, the owner, Monjasa, told AFP.
The shipowner told the French press agency that the vessel’s crew had hidden in the tanker's secure room when the pirates boarded as this was in accordance with the shipping line’s onboard anti-piracy emergency protocol.
"Onboard communications channels are currently down, and we are working with the local authorities to establish communication to understand the situation on board and provide all the support needed by the crew to overcome these dreadful events," Monjasa said.
The shipping line added that the vessel had been “sitting idle" when the pirates boarded.
The nationalities of the crew members have not been revealed to the media.
A Pointe-Noire port official said the vessel had sailed into Congolese waters on March 18 and departed on March 22, reaching international waters before it was attacked.
"Three men took control of the ship and since then the crew can no longer be reached," the official told AFP.
According to the International Maritime Bureau's piracy reporting centre, a missing vessel broadcast has been issued for passing ships to report back if they come across the ship.
The Maritime Information Cooperation and Awareness Center (Mica) says there has been a decline in piracy incidents in the Gulf of Guinea, which has long been notorious for attacks. Mica’s latest report shows that three ships were attacked in the area in 2022 compared to 26 in 2019.