Gunmen in Nigeria kidnapped six Filipino workers during an attack on an oil service vessel in the Niger Delta, a private security source said on Saturday. A speedboat carrying 12 gunmen attacked the vessel and took six hostages, including the boat's captain and two engineers.

"The vessel was attacked in-between Port Harcourt and Bonny," the source said.

No group has claimed responsibility for the attack.

More than 200 foreigners have been kidnapped in the Niger Delta, the heart of Nigeria's oil sector, since early 2006. Almost all have been released unharmed.

In a separate incident, gunmen on Saturday released a Briton, kidnapped more than two weeks ago in southern Nigeria.

"We can confirm a British national, kidnapped on Sept. 15 in Port Harcourt, Nigeria, was released on Oct. 4. He has been visited by consular staff and is safe and well," a British foreign office spokesperson said.