Ukrainian and Russian officials have warned European natural gas supplies are at risk because of lingering contractual disputes that grew out of the political upheaval in Ukraine.
European consumers get about a quarter of their gas needs met by Russia, though the bulk of those supplies run through the Soviet-era gas transit system in Ukraine.
Russian Ambassador to the European Union Vladimir Chizhov told Russia's state news agency RIA Novosti the South Stream pipeline, which avoids Ukrainian territory, was more important than ever.
"I believe the relevance of the South Stream project has risen amid the Ukrainian crisis, because we have already heard not threats, but hints from Ukrainian authorities, including interim Prime Minister [Arseniy] Yatsenyuk, of yet another attempt to disrupt the transit of Russian gas," he said Wednesday.
Yatsenyuk is working with European neighbors to reverse the flow of natural gas in order to protect Ukraine's economy from possible supply disruptions and the price hike for supplies from Russian gas company Gazprom.
European leaders have said they're reluctant to embrace Gazprom's South Stream pipeline given the already heavy role the company plays in the region.