Russia and Ukraine have agreed on the details of an observation mission designed to facilitate the resumption of gas supplies to Europe, DPA quoted officials in Brussels as saying Friday. "There is now agreement on the details of the monitoring mission. It is now imperative that the gas starts to flow to the European Union without any further delay," the European Commission said in a statement. The breakthrough, which followed overnight talks between Brussels, Kiev, Moscow and Prague, came after Ukraine agreed to host Russian monitors and Russia agreed to have Ukrainian observers stationed in Russia. "If a multilateral commission for monitoring gas transits through Ukrainian territory is created, Gazprom will, of course, offer the monitoring commission every opportunity to work at gas-measuring stations in Russia on the border with Ukraine," Gazprom chief Alexei Miller said in a statement. Russia's insistence on having its own monitors in Ukraine was blamed for the breakdown of all-day talks held in Brussels on Thursday. About a dozen EU monitors will also travel to Ukraine to ensure that Russian gas is not siphoned off as it travels to Europe through Ukrainian pipelines, as alleged by Moscow. A first group of monitors was expected to arrive in Kiev later on Friday, with the rest joining the mission on Saturday, officials in Brussels and Prague said. The crisis, sparked by a commercial dispute between Russian state- owned Gazprom and Ukraine's monopoly Naftogaz, escalated this week when Gazprom progressively closed the taps on gas destined to Europe through Ukraine. The stand-off has forced many European countries to tap into their gas reserves and has left thousands of homes without heating at the height of winter. Talks in Brussels between top officials from Gazprom, Naftogaz and the EU broke down Thursday amid mutual recriminations. The European Commission and the Czech presidency of the EU then held further talks overnight with Russian Prime Minister Vladimir Putin and Ukrainian President Viktor Yushchenko. Representatives from the two companies were again invited to Brussels on Friday to attend a Gas Coordination Group meeting designed to assess the impact of the shortfalls. Russia supplies roughly 25 per cent of the EU's total gas consumption, and 80 per cent of that total passes through Ukrainian pipelines.