A gas pipeline was left burning on Sunday evening after a bomb attack near the Havana field, 40km north of Kirkuk

"A fire broke out after the explosion, caused by saboteurs at 10pm (1900 GMT)," said a Northern Oil Company official. "Firefighters are on site trying to contain the fire," said the official on Monday. 

A second explosion set ablaze a nearby oil pipeline, police said, without being able to say what caused the blast.

Firefighters were unable to get close to the fierce fire, the result of what the NOC said was the first such attack in the area north of Kirkuk in four months.

Last Thursday, a pipeline linking Kirkuk to the oil refinery town of Baiji, north of Baghdad, was attacked by a rocket.

According to the interim Iraqi government, persistent attacks on the country's oil resources have caused losses of $7-$8 billion in much-needed oil export revenue.

US soldier killed 

Separately, one US soldier was killed and another was wounded in an attack on a military base in Iraq, the US army said on Monday.

The attack occurred on Sunday at a base near Samarra, 100km north of Baghdad, an army statement said.

The death was a result of indirect fire, probably a mortar round, it added.

Fighters frequently fire mortars at US bases, but generally cause little damage.