In an interview with Vesti TV on Monday, Alexander Medvedev said Gazprom would stick with its South Stream project and stay out of Nabucco.
"Unlike in the case of Nabucco, we have everything we need for this project [South Stream] to materialize," he said. "We have gas, the market, experience in implementing complex projects, and corporate management."
The executive said Gazprom was not prepared to split its operations between two projects simultaneously.
"You chase two rabbits, you catch neither. We have a rabbit we know, and we will chase it," he said.
The $10 billion Nabucco pipeline, backed by the European Union and the U.S., is intended to link energy-rich Central Asia to Europe through Azerbaijan, Georgia, Turkey, Bulgaria, Romania, Hungary and Austria, bypassing Russia and Ukraine. Construction has been tentatively scheduled to begin in 2010.
The South Stream pipeline is designed to annually pump 31 billion cubic meters of Central Asian and Russian gas to the Balkans and on to other European countries, but its capacity could be increased by a further 16 billion cu m. The project involves Bulgaria, Serbia, Hungary, Italy and Greece.
Russia's transit disputes with its former Soviet neighbors have raised concerns in Europe about too much energy dependence on Russia.
Russia cut off gas supplies to Ukraine on January 1 after failing to reach a deal over debt and prices for 2009 in late December, and later halted gas deliveries to Europe, saying Ukraine was stealing transit gas. Kiev denied the accusation.