Updated

A large fire burned at a government oil and gas complex in northern Iraq on Sunday, but it was not known whether it was caused by an accident or sabotage, officials said.

Firefighters and Iraqi soldiers backed by the American forces were fighting the blaze, which began about 5 a.m., said police Capt. Imad Abdullah of the area's oil pipeline protection force.

No casualties were reported.

Abdullah said the fire covered the whole North Oil Co. complex near Kirkuk and that pipelines were closed that normally carry oil and natural gas to refineries and power stations in Beiji, 50 kilometers (30 miles) to the southwest.

It was the biggest fire at the complex in five months, an official at North Oil Co. said on condition of anonymity because he isn't authorized to speak as a company spokesman.

He said an initial investigation indicated the fire was started by a fuse near a pool of oil, but that it wasn't known if the blaze was accidental or started by insurgents.

Militants often attack state oil and gas facilities in northern Iraq, usually setting fire to pipelines that carry supplies from one refinery to another.