(Corrects spelling of ship name in Oct. 29 story to MV Pomerenia Sky in second paragraph from MV Pomerania Sky.)

WARSAW/ABUJA (Reuters) - Pirates boarded a container ship off the coast of Nigeria, seizing 11 crew including eight from Poland, the vessel’s management firm and Polish state media reported.

The attackers struck the MV Pomerenia Sky, bound for the Nigerian port of Onne, early on Saturday and abducted 11 of the crew, Midocean (IOM) Ltd said in a statement on Sunday. The firm added that nine others remained on board and were unharmed.

“Our priority is securing the earliest release of the 11 crew who have been taken and we are working closely with our partners and the local authorities to achieve that,” Midocean said.

“The families of those crew members taken are being kept informed of the situation,” said the company. It added the vessel had proceeded to safe waters.

A Nigerian navy spokesman said they had begun an investigation and search and rescue operation as soon as the incident was reported, and would provide an update soon.

Midocean declined to say where the kidnapped crew members were from, but Polish state media, citing Foreign Minister Jacek Czaputowicz, said eight of them were from Poland.

The nationality of the three other abducted crew members was not immediately clear.

Kidnappings and piracy in Nigeria and the Gulf of Guinea are common.