Moscow/Kiev  - Russia on Saturday approved a European Union initiative for international observers to monitor Russian gas deliveries via Ukraine, Russian Prime Minister Vladimir Putin said.

But the mandate - a key demand by Moscow to lift its embargo of gas supplies - must still be approved by the Ukraine.

After sealing the deal, Putin, Czech Prime Minister Mirek Topolanek, whose country currently holds the EU presidency, was expected to travel to Kiev in a push for a way out of the crisis that was depriving Europe of gas in the dead of winter, Ukrainian officials said.

Meanwhile, the first EU observers to Ukraine began work monitoring shipments on Saturday, Ukrainian officials said, raising hope that the EU was nearing a resolution to the crisis.

A spokesman for natural gas transportation company Ukrtransnafta, Volodymyr Trikolich, said Russian observers who were part of the expert team would receive full access.

Putin accused Ukraine of "a gas blockade" of Europe. He said a signed accord was essential to control the stream of gas would reach Europe.

"As soon as the mechanism of control starts working, we will send gas through the system. If we see that it is stolen again, we will again cut flows," he was quoted by news agency Interfax as saying.

Experts said it would then take almost two days for gas pumped from Siberia to travel downstream.

If Gazprom reopens the gas taps, Ukraine will remain without gas as long as it remains in a deadlock in its contractual dispute with Russia that sparked the original cuts.

"Our actions do not aim to worsen but rather to help Ukraine get rid of crooks and bribe-takers and make its economy more transparent," Putin added, saying that internal political squabbles in Ukraine were at the heart of the crisis.

Russia accuses Kiev of stealing gas meant for Europe. It began reducing its shipments to the former Soviet state on January 1 over a dispute over pricing for 2009. By Wednesday, it had halted all gas exports.

The crisis over gas is growing only more severe for Europe, Russian Prime Minister Vladimir Putin said Saturday, blaming Ukrainian intractability.

"We hope you can convince the Ukrainian party to sign the document," Putin told Topolanek Saturday.

The Czech premier, according to EU delegation sources, presented Putin with a fifth draft of the mandate for the observer mission as Gazprom and Ukraine's state-owned Naftogaz bickered over the details and length the mission.

The deal has been verbally approved by Ukrainian leaders Viktor Yushchenko and Prime Minister Yulia Tymoshenko, Topolanek said Saturday.

"I think there won't be any obstacles to (the mandate) being signed by Ukraine," he said at a press conference in Moscow.

Earlier, Topolanek promised to "stay in the region until we get the gas flowing."

EU member states in central and southern Europe continued to be hard hit by Russia's shut-off of all gas supplies through Ukraine, with Slovakia relying on gas supplies from Poland and EU neighbour Serbia seeking emergency help from Germany, Austria and Hungary.

By far the most critical situation, though, is faced by non-EU members Serbia, Bosnia-Herzegovina, Macedonia and Moldova, which have no reserves left.

About a quarter of the EU's gas needs are met by Russian gas, 80 per cent of which reaches European clients via Ukraine.

EU experts worked Saturday at Ukrtransnafta's headquarters inspecting volume counting equipment and company records, Trikolich said at a Kiev press conference.

The advance team of eight EU technicians arrived in Ukraine on Friday as part of a Brussels plan to end bickering between Kiev and the Kremlin over natural gas shipments.

A total 18 observers will work in Ukraine until the stand-off between Russia and Ukraine over gas shipments is resolved, EU officials said Friday.

The actual field locations of the EU observers for the monitoring mission had not been made public by late afternoon Saturday. (dpa)