An explosion hit the Turkish-Iraqi pipeline, causing a fire and stopping oil flow to Turkey, Turkish security sources and an Iraqi official said Monday. The cause of the fire was not immediately clear but suspicions are running high that Kurdish rebels, who have in the past targeted the pipeline, or oil smugglers may have sabotaged it. The fire started in the Silopi and Cizre districts of Sirnak province near the Iraqi border following the blast overnight Sunday on the Kirkuk-Ceyhan pipeline, said local security sources, adding that firefighters were trying to put out the flames. "Iraqi oil exports from Kirkuk to Ceyhan have stopped because of sabotage of the oil pipeline in Turkey near the Iraq-Turkey border," Iraq Oil Ministry spokesman Assem Jihad said in Baghdad. He said the blast "caused a big fire and stopped exports" but did not say who was responsible for it. "We call on Turkey to use the alternate pipeline (used in emergencies) to avoid stopping the pumping of oil," he added. The outlawed Kurdistan Workers' Party (PKK), listed as a terrorist group by Turkey and much of the international community, have sabotaged the pipeline several times in the past as part of an armed campaign against the Ankara government. The 970-kilometre (600-mile) pipeline runs from Iraq's northern oil hub of Kirkuk to the port of Ceyhan on Turkey's Mediterranean coast, pumping 450,000 to 500,000 barrels of crude oil per day. Iraq depends on oil sales for the vast majority of government income. The oil-rich nation exported some 2.515 million barrels per day in July, earning about $7.535 billion in revenues.