Russia and Ukraine have reached an agreement on the details of a monitoring mission aimed at ensuring gas supplies to Europe, the European Commission said in a statement.

"It is now imperative that the gas starts to flow to the European Union without any further delay," said the commission, the executive arm of the EU.

Ukraine agreed to allow Russian experts to join the EU mission to monitor gas flow through the country.

Earlier, Russian Prime Minister Vladimir Putin told Czech Prime Minister Mirek Topolanek, whose country holds the EU's rotating presidency, that Moscow was ready to accept EU monitors along with officials from Russia's state-run gas monopoly Gazprom and its Ukrainian counterpart Naftogaz.

The Czech Republic took over EU's rotating presidency in the new year.

European monitors will arrive in the Ukrainian capital Kiev on Friday. Naftogaz spokesman Valentyn Zemlyansky said they will tour gas pumping stations together with Russian experts.

Russia cut gas supplies to Ukraine on Jan. 1 over a payments dispute, and shut off gas intended for Europe via Ukraine on Wednesday.

The shutoff left thousands of European families without heating at the height of winter, prompting EU action to broker a deal to end the row.

The EU depends on Russia for a quarter of its gas supply, the bulk of which comes via Ukraine.

(Xinhua News Agency January 9, 2009)