A pipeline pumping gas from Ukraine's Ananyev to Izmail via Odessa ruptured at about 05:30 a.m. local time (02:30 GMT) near Tiraspol, the capital of the unrecognized republic of Transdnestr. No casualties or damage were reported as a result of the blaze that followed.
Deliveries of Russian gas to the Balkans via Moldova have been cut by 40% due to the rupture, Gazprom said in a statement.
The Russian energy giant said that natural gas supplies to Romania, Bulgaria, Macedonia and Greece were unaffected.
Meanwhile, the Ukrainian national energy company Naftogaz said that Russian gas deliveries to the Balkans via Ukraine had dropped one-third after the accident.
Valentyn Zemlyanskiy, Naftogaz press secretary, said that daily gas supplies were cut from 40 million to 24 million cubic meters.
"One [pipeline] section out of three was closed down and supplies were diverted to the remaining two," he said.
According to preliminary information, the rupture of the pipeline could have been caused by simple wear and tear.
Transdnestr Industry Minister Pyotr Stepanov said that the pipeline could be repaired by Friday evening.
The Blue Stream pipeline is the largest Russian-Turkish energy project to date.
