Gunmen have attacked a cargo vessel and kidnapped 12 foreign crew members in the waters off the coast of Nigeria's oil-rich Niger Delta region, a navy officer said on Saturday.

"The attack took place some time last evening and only one ship was involved.... One of the crew members was injured from gunshots and 12 were taken hostage," Nigerian navy spokesman David Nabaida told AFP.

Nabaida said information he has is that the attacked vessel, the BBC Polonia, is German-flagged, but according to the MarineTraffic.com website, it is an Antigua Barbuda registered ship which was heading to Nigeria's Onne port, situated on the Bonny estuary, close to the oil hub of Port Harcourt.

The navy managed to board the vessel and sailed it to Bonny anchorage, Nabaida said.

One of the crew who was injured in the attack is Ukrainian and is in a stable condition at an Nigeria Liquefied Natural Gas hospital in Bonny, he added.

No group has yet claimed responsibility for the attack.

Hundreds of people, both locals and foreigners, most but not all of them linked to the oil sector, have been kidnapped in the restive Niger Delta in recent years.

Most have been released after a few days or a few weeks in captivity, very often after the payment of a ransom.