MOSCOW - RUSSIAN state gas giant Gazprom accused Ukraine on Friday of 'stealing' gas from Russian exports meant for clients in Europe, a charge immediately denied by Ukraine.

'The Ukrainian side openly admits it is stealing gas and has no shame about it,' Gazprom spokesman Sergei Kupriyanov said at a briefing for journalists in Moscow.

Mr Kupriynavov put the amount of gas that he said had been illegally 'siphoned' from pipelines crossing Ukrainian territory at 21 million cubic metres since Thursday.

Ukraine's state gas company Naftogaz immediately denied Gazprom's accusation of gas theft, but said it had 'removed' gas from Russian volumes being shipped to European customers for 'technical' reasons.

'We are not stealing gas. We are removing gas for technical purposes, in order to ensure the transit of Russian exports' to Europe, Valentin Zemlyansky, spokesman for Ukraine's state gas company Naftogaz, told AFP in Kiev.

Both Russia's accusation and Ukraine's qualified denial called into question the assurances both countries have repeated in recent days that shipments of Russian gas to Europe would not be endangered despite the dispute.

Mr Kupriyanov also charged that Ukraine had refused to allow Russia to pump the volume of gas it needs to pump for European customers through the pipeline network that crosses Ukrainian territory.

'Regarding the next 24 hours, the Ukrainian side did not agree to the transit volume required by us,' he said.

'We made a request for 303 million cubic metres but were refused this and permitted 296 million cubic metres.'

Separately, a senior Russian diplomat announced that Russia was calling for an emergency session of the European parliament and said a letter to this effect had been delivered to the EU body.

'We propose calling an emergency session of the European parliament in order to give the Russian side a chance to express its views,' Deputy Foreign Minister Alexander Grushko said on Russia's Vesti-24 television news network.

The latest testy exchange ratcheted up tension in the Russia-Ukraine gas crisis and came a day after Gazprom halted gas shipments to Ukraine over a dispute on payments and pricing.

Despite the assertion from both sides that 21 million cubic metres of gas had been siphoned from Russia's transit exports, there were no immediate reports of shortfalls from clients in western Europe.

The EU's executive Commission said there had been no noticeable drop in the supply of Russian gas to European nations.

'This morning volumes were normal,' said Ferran Tarradellas, spokesman for EU Energy Commissioner Andris Piebalgs, adding that the Europeans were monitoring the situation very closely.

Some customers had reported report brief shortfalls during a similar crisis in 2006, when Russian gas supplies to Ukraine were also shut down over a price dispute. -- AFP