EU and Russian leaders met in Stockholm on Wednesday for a summit dominated by energy issues, as Europe hopes to avoid an interruption of Russian natural gas supplies via Ukraine this winter.

Sweden, current holder of the European Union presidency, was also to press Moscow on the sensitive topic of human rights, climate change and the global economy.

"We hope to have a good discussion today on the climate, energy and economic issues," Swedish Prime Minister Fredrik Reinfeldt said as he opened the Stockholm meeting with Russian President Dmitry Medvedev.

The two held bilateral talks just before the summit. Swedish-Russian relations are traditionally complex but the atmosphere was seen as lightened by Stockholm's recent decision to let the Russian-led Nord Stream gas pipeline pass through its economic zone of the Baltic Sea.

"This project is mutually beneficial ... (and) aims to make European energy supplies more diversified," Medvedev told reporters.

On Monday, Russia and the EU signed an energy early warning protocol they said would help avert a sudden disruption of gas supplies. Reinfeldt and Medvedev were to formally sign the deal Wednesday.

Russia supplies a quarter of the gas consumed in the European Union, with most of it transiting Ukraine, which regularly has rows with Moscow over bills.

Russia has warned in recent weeks that Ukraine, which has been badly hit by the global economic crisis, could have trouble paying its gas bills to Moscow this winter.

The money disputes have led to serious gas supply disruptions across Europe in recent years. In January, Russia cut off gas to more than a dozen European countries for two weeks.