Russian officials say repairs will take two or three days, leaving Georgia and Armenia facing a potential energy crisis in the depths of a harsh winter.
A spokeswoman for Georgia's Energy Ministry, Teona Doliashvili, said Georgia had one day's gas reserves. Shushan Sardarian, a spokeswoman for Armenia's gas distributor, said Armenia is drawing on its reserves to keep households supplied.
However, Azerbaijan has since reportedly agreed to provide natural gas to Georgia.
Saakashvili said he believed Russia had deliberately cut off Georgia's gas supply to pressure it into surrendering ownership of its domestic gas pipeline network to Moscow.
He said Russia had chosen the coldest time of the year in Georgia to cut gas supplies.
Russian Emergency Situations Ministry spokesman Viktor Beltsov initially said the blasts appeared to be accidental, but Russia's deputy prosecutor-general in charge of the North Caucasus, Nikolai Shepel, said officials are investigating the possibility of sabotage.
The Russian Foreign Ministry described Saakashvili's comments as "hysterical" and "confused," adding that they could have serious implications for bilateral relations.
A spokesman for the Russian gas giant Gazprom said that any politicizing of the accident is unacceptable.
(compiled from agency reports)