Two guards from Benin were shot in the Gulf of Guinea when the tanker they were working on was hijacked by pirates.
The Luxembourg-registered product tanker, St Marseille was attacked by five armed pirates in the Bay of Cotonou on Tuesday morning.
The pirates boarded the vessel and shot the guards, but fled after finding no cargo on board.
The two guards are now said to be in a stable condition in hospital.
The St Marseille belongs to ST Management. This is the third small product tanker to have been attacked by pirates in the region in the last month.