Ukraine said on Tuesday it was treating an explosion on a pipeline carrying Russian natural gas to the rest of Europe as a possible "act of terrorism."
The government, which is facing a rebellion by pro-Russian separatists in east Ukraine, said the blast in central Ukraine — one day after Russia cut gas supplies to Kiev in a pricing dispute — did not disrupt gas flows to the European Union.
But Interior Minister Arsen Avakov said: "Several theories of what happened are being considered including the key theory — an act of terrorism."
"According to local residents, they heard two big bangs just before the explosion which could indicate they were deliberate explosions."
The Energy Ministry also suggested there may have been foul play, without speculating who might have been behind the blast.
"It is not the first attempted terrorist attack on the Ukrainian gas transportation system," the ministry said in a statement, referring to two explosions on transit pipelines in the western part of the country in May.