An explosion ripped through a pipeline carrying oil from Iraq to southern Turkey causing a large spill, Anatolia news agency reported.
The blast occurred late last night, in a section of the pipeline in the mainly Kurdish province of Sanliurfa in southeast Turkey, Anatolia said, adding that initial findings blamed the incident on an abrupt change of pressure in the network.
Separatist Kurdish rebels, active in the region, have in the past bombed the twin pipeline, which runs from the northern Iraqi city of Kirkuk to Turkey's Mediterranean port of Ceyhan and has a capacity to carry some 70 million tonnes of crude a year.
The authorities turned off the taps as oil spilled as far as two kilometres from the spot of the blast, reaching the shores of a major dam in the region, Anatolia said.
It was not immediately clear when the conduit would be re-opened.
The pipeline has been often sabotaged also by insurgents inside Iraq since the US-led invasion of the country in 2003.
It carried about 40 million barrels of Iraqi oil to Ceyhan last year, according to Turkey's state-run oil and gas company BOTAS.
In August, a powerful blast disrupted for three weeks the flow through another oil pipeline in Turkey, which carries Azeri oil from Baku to Ceyhan, and separatist Kurdish rebels claimed responsibility for the explosion.
Unrest in Turkey's southeast has recently flared amid an intensified Turkish military crackdown on the rebels and reports that their jailed leader, Abdullah Ocalan, was mistreated in jail.