The EU's energy chief warned Moscow on Monday that the Ukraine crisis was hardening Brussels' stance on a gas pipeline that Russia's Gazprom is planning to build in southeast Europe.
Next month, construction is due to begin on the South Stream pipeline, which would run from the Black Sea to Austria. Gazprom has long sought to challenge EU competition rules to make the project more commercially appealing.
But in an interview with the Financial Times, Günther Oettinger, the EU's energy commissioner, said he was not inclined to waive the rules, particularly in light of events in Crimea and eastern Ukraine.
"These days, with Ukraine, we are more and more defensive related to Russian pipelines than one year ago," he said. "These days, exemptions are not my priority for Gazprom."
EU competition laws called "the third energy package" are intended to break monopolistic supply chains and would require Gazprom to grant other suppliers access to South Stream, possibly to a point where it could be restricted to providing only half of the pipeline's gas. The intention is to foster greater competition in EU energy markets.
Last week, Russia launched a complaint at the World Trade Organisation to try to overturn the EU's rules but Mr Oettinger said Moscow would not be granted any leeway. "It is not realistic to expect that we change these rules in the next days or the next years," he said.
"No doubt there is a different culture. In Russia, the government and Gazprom, they prefer to dominate the whole chain from production upstream . . . to downstream power plants."