Iraq's northern oil exports were halted Thursday after a vital pipeline to Turkey was hit by a big attack, said an official for oil security in the region.

"The pipeline with Turkey was shut down," said Ahmed Hassan Ghafif, head of security for gas and oil pipelines in northern Iraq.

"The Iraq-Turkey oil pipeline targeted this afternoon is about 40-inches wide and today's attack can be considered the biggest since sabotages started a year and a half ago," he added.

It was reported that the bomb attack happened at 6:30 PM (14:30GMT) on a road next to the pipeline near the town of Riyadh, 50 km south of Kirkuk. The oil-rich city was engulfed in a thick cloud of black smoke.

The pipeline was attacked on its southern section, where it heads to Iraq's largest oil refinery in Baiji, before cutting back north toward Turkey.

Fire department, National Guard and Iraqi police have been making efforts to prevent the oil from spreading as a first step. It was predicted that 48 to 72 hours were needed to extinguish the fire.

Kirkuk oil has been pumping 600,000 to 800,000 barrels per day recently. Repeated sabotage of Iraq's oil industry has cost the country more than US$ 1 billion in revenue.

(Xinhua News Agency September 3, 2004)