Prague - Pressure began to drop Friday in pipelines that supply Russian natural gas to the European Union at the bloc's border with Ukraine, a result of Russia's cut in gas delivery to Ukraine that began Thursday, a Czech energy official said.

"It is so far only a decrease in pressure. The volumes remain the same," Czech Republic's energy envoy Vaclav Bartuska told Deutsche Presse-Agentur dpa. He said that the pipeline pressure was down on Ukraine's border with Poland, Slovakia and Hungary.

Volume cuts were however imminent, according to Bartuska. "The Ukrainian side told us that volumes will be down tomorrow (Saturday)," he said, adding that it was crucial for the Czech EU presidency to confirm such information with the involved member states.

Slovakia relies on Russia for all of its gas needs, while Hungary gets 65 per cent and Poland 46 per cent of its gas there, the International Energy Agency said.

Czech EU presidency spokesman Jiri Frantisek Potuznik told dpa that Prague will act only after the pressure drops are "confirmed on an official level." He said that the presidency is to hold urgent consultations with member states on forthcoming steps.

Ukraine's government earlier on Friday raised the stakes in its gas conflict with Russia, saying that Gazprom's ongoing gas shipments to Europe could be confiscated.

The statement came on the day when Ukrainian officials visiting Prague failed to persuade the EU to get involved in the dispute.

The Czech EU presidency resisted the call for brokering the row and repeated that the 27-member bloc will step in only after the pipeline pressure drops on the EU border with Ukraine.

Bartuska would not say whether Ukraine was siphoning off gas for Europe in a bid to force the EU into entering the dispute. "Both Ukraine and Russia are interested in having the EU on their side," the envoy said.

"We do not want to be and will not be an arbiter. It is a commercial dispute. It is not our goal to determine who is right," he added.

The row between the two countries escalated on Thursday when Kremlin's gas export monopoly Gazprom cut supplies to Ukraine.

The shutdown followed a collapse in talks on a new delivery contract and payments for Ukraine's alleged outstanding debt for Russian gas.

Officials in Prague are also planned to meet a "key" Gazprom representative on Saturday, Bartuska said.

The EU is largely dependent on Russian gas, some 80 per cent of which arrive via Ukraine. (dpa)