PORT HARCOURT, Nigeria -- Pirates attacked a ship being used by an oil servicing company in waters off southeastern Nigeria on Saturday, killing two Nigerian naval guards and kidnapping four foreigners, the navy said.
"The incident was somewhere around the Niger Delta, where an oil servicing company was attacked by gunmen. We lost two of our men and four expatriates were abducted, one Malaysian, one Iranian," navy spokesman Commodore Kabir Aliyu said.
He said a Thai and an Indonesian were also taken, but had no immediate further details.
Watch World News videos on NBCNews.com
Security in the Delta has improved since militant activity shut down nearly half of Nigeria's oil output around the middle of the last decade, thanks to an amnesty between various militant factions and the government.
But the situation remains volatile and inflamed by organized crime and local political rivalries.
Piracy and kidnapping in the Delta and offshore are common, and West Africa's oil-rich Gulf of Guinea is second only to the waters around Somalia for the risk of pirate attacks, which drives up shipping insurance costs.
They are seen as more of a criminal enterprise making huge sums for armed gangs than as anything political.
Stay informed with the latest headlines; sign up for our newsletter
Nigerian pirates usually release kidnapped crew members after their cargo has been looted, rather than hold them for ransom.
More world stories from NBC News:
- UN General Assembly condemns Syrian regime; Russia and China balk
- Cholera threatens displaced Congolese
- Belarus, Sweden kick out ambassadors as teddy bear war heats up
- Reuters confirms hackers posted fake Syria news story on its service
- Olympic hosts: Londoners open their homes to the world
- President: Mexico gang-related deaths fall by 15 percent in 2012
- Baby elephant orphaned in slaughter finds a foster mom
- Images: The lives of Syrian rebels fighting for freedom