Georgia's president has accused Moscow of serious acts of "sabotage" after gas blasts on Russian pipelines cut off supplies to Georgia and Armenia.
Mikhail Saakashvili told the BBC the near simultaneous attacks close to Georgia's border were pre-planned actions orchestrated by Russia.
An electricity transmission line was also destroyed as Georgia experiences extremely cold weather.
Russia's foreign ministry dismissed Mr Saakashvili's remarks as "hysteria".
Russian prosecutors earlier described the attacks as deliberate criminal acts and said an investigation was under way.
Georgia has no gas reserves and was due to run out of gas on Sunday evening, correspondents say.
Relations between Georgia and Russia have been tense since Mr Saakashvili was swept to power by the so-called "Rose Revolution" in 2003, pledging to lead his nation on a pro-Western course.
'Planned attacks'
The two explosions occurred on the main branch and a reserve branch of the Mozdok-Tbilisi pipeline in the Russian border region of North Ossetia at around 0300 local time (2400 GMT).
The electricity transmission line in Russia's southern region of Karachayevo-Cherkessiya - also near the Georgian border - was brought down by an explosion just hours later.
Speaking to the BBC, Mr Saakashvili said there was now huge pressure on his country's energy system, as it was experiencing its coldest weather in more than 20 years.
He said all gas supplies to Georgia were now cut off as was 25% of the electricity supply.
Mr Saakashvili said the gas pipeline was blown up in "an area fully under Russian control... with a heavy presence of Russian border guards", where there were no local insurgents.
