TIKRIT, Iraq, AP -An explosion shut down an oil pipeline near the northern city of Beiji on Wednesday, a police official said.

The pipeline transports oil from the northern oil center of Kirkuk to refineries in Beiji, from where it is pumped via the country”s export pipeline to the port of Ceyhan, Turkey.

The blast occurred early Wednesday at Fatiha, 10 miles northeast of the Beiji refinery, said Mattshar Abdullah, who works on a special Iraqi police force set up to guard oil pipelines and refineries.

The Kirkuk-Beiji pipeline is critical to Iraq”s oil export operations. Once Beiji refinery”s crude oil needs are met, excess amounts are pumped through a separate export pipeline to Turkey.

That line is only intermittently open, however, since incessant insurgent sabotage has shuttered it regularly since the U.S.-led invasion in 2003.

Wednesday”s explosion is the third suspected sabotage attack against a northern pipeline in the past week, Dow Jones Newswires reported. Similar blasts have damaged pipelines in Ishaqi, near Samarra, and Debbs, near Kirkuk.