A major pipeline in Ukraine carrying gas from Russia to the rest of Europe has been hit by a blast which Ukraine's government said could have been an attempted terrorist attack.
The explosion hit the the Urengoy-Pomary-Uzhgorod Pipeline in central Ukraine. No one was reported injured.
The blast occurred after after Russia cut supplies to Kiev in a price dispute, but European and Russian companies said gas exports to the EU were not affected.
Ukraine's Interior Ministry issued a statement which described the blast as "the latest attempt by the Russian side to discredit Ukraine as a partner in the gas sector", Reuters reports.
"Several theories of what happened are being considered including the key theory - an act of terrorism," Interior Minister Arsen Avakov said in the statement.
The Energy Ministry also suggested there may have been foul play, saying it was "not the first attempted terrorist attack on the Ukrainian gas transportation system."
According to AFP news agency, Ukraine's state emergencies service said the blast appeared to have been the result of a puncture or loss of pressure.
Police said the blast on the pipeline happened about two metres below ground.
Earlier on Tuesday, Prime Minister Arseny Yatseniuk told parliament in Kiev that Moscow had blocked attempts to reach a deal in the long-running dispute over the price Ukraine should pay for Russian natural gas and Kiev's unpaid bills.
Moscow has blamed Kiev for the failure to reach agreement, with big differences remaining over the price.
Ukraine has said it will try to restore control of the border with Russia to prevent further violence.
Tuesday's explosion was far from the violence in east Ukraine, where border guards said 30 servicemen had been wounded in an overnight mortar attack near the border.