Eight merchant seamen aboard the Greek-flagged tanker "Happy Land" were abducted by pirates on Tuesday morning as the vessel was anchored two nautical miles from teh port of Limboh, in Cameroon.
The Greek shipping ministry later announced that five of the eight are Greek nationals, with another two being Filipino nationals, and the last man from Ukraine.
One merchant seaman, identified as a 35-year-old Greek third engineer, was injured when a ricocheted bullet struck him.
The ship's master, a 45-year-old Greek national, was among those abducted.
Greece's relevant services in the foreign and shipping ministry were activated to follow developments and liaise with the vessel's owners.