Pirates off Nigeria’s oil-rich south have stormed a small oil tanker, kidnapping six sailors, the International Maritime Bureau (IMB) said on Thursday, the latest in a string of such attacks.

The Apecus, a Palau-flagged petroleum products tanker of 3,100 deadweight tonnes, was attacked on Friday as it was anchored off Bonny Island, south of oil hub of Port Harcourt, according to the IMB Piracy Reporting Centre.

“An anchored tanker was boarded by unauthorised persons who kidnapped six crew and escaped,” the piracy watchdog said, adding that the rest of the crew were reported to be safe. No details of their nationalities were given.

“The Nigerian Navy was notified and an investigation into the incident has been launched,” the IMB added. The Navy was not immediately available for comment.

Pirates normally seize sailors for ransom.

Nigerian pirates recently hijacked another merchant ship, robbing the vessel’s crew. The unidentified ship was freed in the Gulf of Guinea by a Spanish warship on April 9 after four days.

Days later, on April 15, four armed men boarded another anchored oil tanker, also in the Bonny River area, but Nigerian naval guards onboard fought the pirates off.

Nigeria has been a hotspot for piracy incidents over the past decade. The country reported 14 pirate attacks for the first quarter of 2019, compared to 22 in the same period in 2018.

A report by IMB early this month attributed the decline to the Navy’s increased efforts to “actively respond to reported incidents by dispatching patrol boats.” (AFP)