Gazprom Chief Executive Officer Alexei Miller met with Executive Director of Bulgarian gas company Bulgargaz Dimitar Gogov in Moscow.
Both sides, Gazprom said in a statement, "laid stress on the successful implementation of the South Stream project."
Gazprom officials had a recent ground-breaking ceremony for construction of the South Stream pipeline, which would move Russian gas to southern Europe.
Doubts have emerged over the project's implementation, however. Marlene Holzner, a spokeswoman for European Energy Commissioner Gunter Oettinger, told Radio Free Europe/Radio Liberty last week that Gazprom hasn't offered any formal declaration about the pipeline's route.
Oettinger met Wednesday with Russian Energy Minister Alexander Novak. Holzner told online news magazine New Europe that Novak "did not mention South Stream" during the talks, however.
South Stream is meant to diversify Russia's gas export options and avoid geopolitically sensitive transit routes in Ukraine. Europe aims to break the Russian grip on the regional energy sector through a network of pipelines dubbed the Southern Corridor.