Chevron Forced to Close Oil Facility in Nigeria After Attack by 'Avengers' Militant Group

Militants have attacked a Chevron facility in Nigeria's oil-rich Niger Delta, forcing the US energy giant to suspend operations and reviving fears of an insurgency in the region.

The attack overnight on Wednesday targeted the Okan offshore facility located in the western part of the Niger Delta off the coast of southern Nigeria, according to Chevron Nigeria Limited, an operator of a joint venture with the Nigerian National Petroleum Corporation (NNPC).

Chevron told the Associated Press on Friday that the the facility was still shut down on Friday. The company said it is assessing the situation and deploying resources to respond to a subsequent oil spill.

"It will not affect our commitment to export crude," Chevron spokesman Deji Haastrup told the AP, declining to provide any figures on the impact the incident would have on its output.

There were no immediate details provided on casualties, although some reports have said that a security guard was killed.

A group known as the Niger Delta Avengers claimed responsibility for the attack, and said in a statement that it blew up the platform.

"This is what we promised the Nigeria government since they refuse to listen to us," the group said.

It is the latest in a series of attacks on oil facilities in Nigeria, Africa's top oil exporter. President Muhammadu Buhari has vowed to crack down on "vandals and saboteurs" in the Delta region, which produces most of the country's oil. The same group has said it carried out an attack on a Shell oil pipeline in February, which shut down a terminal that exports 250,000 barrels of oil per day. The incident prompted a new government security operation in the region.

Pipeline attacks and violence have risen in Nigeria's southern swampland since authorities issued an arrest warrant in January for a former militant leader wanted on corruption charges.

Buhari has extended a multi-million dollar amnesty signed with militants in 2009, but upset them by ending generous pipeline protection contracts. The militants say they want a greater share of oil revenues. Crude sales account for around 70 percent of national income in Africa's biggest economy.

The militancy is a further challenge for a government faced with an insurgency by the Islamist militant Boko Haram group in the northeast, as well as violent clashes between armed nomadic herdsmen and locals over land use in various parts of the country.