An attack on a pipeline in eastern Turkey cut off Iranian gas shipments to Turkey overnight and it may take up to a week before they resume, the energy ministry said Friday.
"Work continues to put out the fire," the governor's office in Agri province said in a statement quoted by Anatolia news agency.
"It has been established that the incident was caused by a terrorist attack," around 11:10 pm (2010 GMT) Thursday, it added.
Anatolia said an explosion rocked the region two kilometres (1.2 miles) from Agri, causing the fire.
Firefighters were sent to the site and the pipeline was shut off.
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The governor's office did not identify any perpetrators but Kurdish rebels fighting for a homeland were widely seen as the main suspects.
An energy ministry official speaking on condition of anonymity told AFP that repairs on the pipeline had started and would last about a week.
The shortfall in Iranian gas would be compensated by deliveries from Azerbaijan, and Russia via the undersea Blue Stream pipeline.
Turkey receives between 15 and 18 billion cubic metres of gas a day via the Iranian pipeline which links the western city of Tabriz with the Turkish capital.
Rebels of the outlawed Kurdistan Workers' Party (PKK) are regarded as terrorists by Turkey, the European Union and the United States.
The nationalists want constitutional recognition for the Kurds, regional self-governance and Kurdish-language education in schools.
The Turkish army holds the PKK responsible for the 45,000 deaths the conflict has caused on both sides.