Iran shut its natural gas pipeline to Turkey on Tuesday for maintainance work following a technical hitch, a Turkish energy ministry official told AFP.
The flow of gas was stopped "with the knowledge" of Turkeys state-run gas company BOTAS, the official said.
"The cut is not expected to take long," he said, while Anatolia news agency quoted unnamed officials as saying that the pipeline would remain shut for 24 hours.
Turkey receives between 15 and 18 million cubic metres of gas daily through the conduit, which runs from the northwestern Iranian city of Tabriz to Ankara.
Turkey, which also buys gas from Russia, weathered relatively smoothly the recent crisis between Moscow and Kiev, which left millions in Europe without heating, thanks to the Iranian conduit and a second pipeline with Russia running under the Black Sea.