Four foreign oil workers have been kidnapped in Nigeria's volatile Niger Delta, only hours after 11 Korean and Filipino workers were freed. The workers - including at least three US citizens - were seized off an oil export terminal belonging to Chevron.

On Monday, the main militant group in the oil-rich south said it blew up three oil pipelines in Bayelsa State.
The militants want a larger share of oil wealth. Their actions cut production by more than 25% last year.
The price of oil in London went up to more than $65 a barrel on Tuesday.

"Armed men on two speed boats with rifles and RPGs (rocket-propelled grenades) boarded (the barge). Four American personnel were abducted," a source who asked not to be named told Reuters news agency.

A US diplomat told AFP news agency that he could only confirm that three of the abductees were American.

Many of those kidnapped in the Delta are seized by armed gangs wanting ransom money.

But the militant group, Mend, says it wants a larger share of oil wealth for local communities and recently warned that they would step up attacks on oil installations in the region as "parting gift" to President Olusegun Obasanjo who stands down in three weeks time.

They say the oil pipeline attacks on Tuesday were also in pursuance of their resolve to cripple the Nigerian crude oil export industry.

Mend says it will continue its renewed campaign "indefinitely with attacks on all pipelines, platforms and support vessels".
There are unconfirmed reports of military personnel being arrested in the Niger Delta suspected of collaborating with militants.

The eight Filipinos and three South Koreans, all workers at Daewoo, had been taken at gunpoint from a heavily guarded compound last Thursday.

Their Nigerian driver was later released.

South Korean government officials said the freed hostages were well.

Nearly 100 foreign workers have been abducted this year.