KIRKUK, Iraq, (Reuters) – A bomb blew up and set fire to a crude oil pipeline carrying oil from a town in northern Iraq to the city of Kirkuk, Iraqi and U.S. military officials said on Thursday.

The explosion at around midnight set fire to one pipeline and damaged a second, said the joint U.S.-Iraqi military coordination centre in Kirkuk. Exports were not affected.

The fire occurred in the town of By Hassan, near the disputed city of Kirkuk, 250 km (155 miles) north of Baghdad, police said. “This explosion did not affect the Iraqi-Turkish pipeline, it is for domestic use. In the next few hours we should be able to extinguish the fire,” said a source at the state-run North Oil Company, who asked not to be identified.

Attacks targeting oil pipelines in Iraq have declined in the past year due to improved security as the insurgency and sectarian bloodshed that followed the 2003 U.S.-led invasion begin to ease.