Gunmen attacked at least one ship belonging to an oil services company off the coast of the Niger Delta on Saturday, killing two Nigerian sailors and kidnapping four foreign nationals.

The ship belongs to the Sea Trucks Group, a Nigerian company that works in the oil and gas sector in the Niger Delta and Gulf of Guinea. Sea Trucks and the Nigerian navy said that the attack happened about 35 nautical miles off Nigeria's oil rich coastal area.

The navy's spokesman, Kabir Aliyu, reported that the kidnapped Sea Trucks' employees came from Indonesia, Iran, Malaysia and Thailand. Aliyu said that a helicopter and ship had been deployed to the region to help with search and rescue operations.

Sea Trucks spokeswoman Corrie van Kessel told the AFP news agency that two of the company's ships had come under attack. The Nigerian navy insisted that only one vessel was targeted.

According to the International Maritime Bureau (IMB), there were 32 piracy incidents recorded off the coasts of Benin, Nigeria and Togo in the first half of 2012, up from the 25 documented attacks in 2011.

Nigeria is one of Africa's top oil producers and ranks tenth in the world. Tensions run high in the Niger Delta region, where armed ethnic militias accuse foreign oil corporations and the Nigerian government of marginalizing their interests.

slk/sej (AFP, dpa, Reuters)