U.S. and British oil workers abducted

LAGOS, Nigeria, May 25 (UPI) -- U.S. and British authorities confirm four Britons and three Americans were among a group of foreign oil workers kidnapped by Nigerian militants Friday.

A State Department spokesman says they are in the process of notifying the workers' families and maintaining contact with Nigerian authorities to monitor the situation.

A witness to the kidnappings said some 15 militants used two speedboats to remove the workers from a ship off the coast of Nigeria, The London Telegraph reported.

The abduction brings the number of foreigners currently held hostage in Nigeria to more than 20.

This year alone more than 100 foreign workers have been seized near the Niger delta.

Most of the hostages are freed within days after their employers pay a ransom to their captors.

Nigeria is the world's eighth largest oil exporter but has seen a drop in production of nearly 25 percent in the last 18 months due to a surge in violence.