Brussels  - Russian gas monopolist Gazprom refused on Thursday to renew gas supplies to Europe in return for a mission of European Union experts intended to monitor gas flows from the country through Ukraine, EU officials said.

"Gazprom said no to the mission. We are disappointed, because we believe the Russian side has no reason to refuse and not to allow the resumption of supplies through Ukraine to the EU," Czech energy minister Martin Riman, whose country holds the EU's rotating presidency, told reporters in Brussels.

Gazprom rejected the mission because it wanted to deploy its own observers to Ukraine, a demand Kiev rejected, EU Energy Commissioner Andris Piebalgs said.

"I can't name a date and time when gas will be reinstated," he said. The EU's mission is to deploy to Kiev on Friday, he said.

The two officials were speaking after all-day negotiations with Gazprom chief Alexei Miller and his Ukrainian counterpart, Oleh Dubyna, both of whom flew to Brussels on Thursday to lobby for EU support in their ongoing row over gas prices and contracts.

Russia supplies roughly 25 per cent of the EU's total gas consumption, and 80 per cent of that total passes through Ukrainian pipeline.

Gazprom on Tuesday shut off all gas supplies through Ukraine to Europe, accusing the Ukrainian side of stealing gas meant for EU customers. The dispute has left many EU countries facing gas shortages just as the continent is suffering from one of its coldest winters in decades.

Ukraine rejected the allegation. Miller and Dubyna are now set to fly to Russia for further talks, the Interfax news agency wrote. (dpa)