MV Bonita was anchored off the entrance of Cotonou port when it was boarded by pirates, local authorities say.

Pirates have kidnapped nine crew members of a Norwegian-flagged vessel off the coast of Benin, according to authorities, the latest in a string of abductions in the Gulf of Guinea.

The dry bulker MV Bonita, owned by Norwegian shipping firm JJ Ugland, was boarded by the attackers while at anchor 14km (nine miles) from the entrance of Port of Cotonou, port officials said on Sunday, describing it as “act of piracy”.

The ship was carrying a cargo of gypsum, a mineral commonly used as fertiliser, which was destined for Benin, according to the company, which said its vessel was boarded by pirates in the early hours of Saturday.

Citing safety reasons, the Norwegian shipowner did not reveal the crew’s nationalities or how many had avoided capture.

“The Ugland Emergency Response Team are handling this situation as per contingency plans, and they are in contact with relevant authorities … The families of the crew members have been contacted and will be kept informed by Ugland,” the company said in the statement.

The Cotonou port authority said the ship’s captain was among those abducted, adding that other crew members who are safe are being interviewed as part of an ongoing investigation.

Shipping companies have reported several abductions in the region in recent months, including eight crew members taken from a German-owned vessel off Cameroon in August, and 10 Turkish sailors off the coast of Nigeria in July.

While piracy has decreased worldwide, West Africa’s Gulf of Guinea is a high-risk area for abductions and armed robbery, the International Maritime Bureau (IMB), a unit of the International Chamber of Commerce, said in a statement last month.

“The region accounts for 86 [percent] of crew taken hostage and nearly 82 [percent] of crew kidnappings globally,” the IMB said.

Pirates sometimes divert ships for several days, long enough to plunder the cargo and demand huge ransoms before freeing the crew.