Moscow - Russian export monopoly Gazprom said Tuesday it has been ready "any minute" to sit across the negotiating table from Ukrainian officials in a deadlock over gas supplies that has drastically cut volumes of Russian gas reaching Europe via Ukraine.

"We are surprised by the (Naftogaz Ukrainy's) announcement it was ready to continue talks on January 8, we are ready to start talks at any minute, given the critical situation," a spokesman for the company Sergei Kupryanov said in a televised statement.

"Gazprom" was and will be the reliable supplier of gas," he added.

But Kupryuanov confirmed Gazprom had cut supplies to European customers via Ukraine. His were the first comments from the company since European customers began seeing steep pressure drops in pipelines Tuesday morning.

Gazprom supplied about 65 million cubic metres on Tuesday, compared with 260 million on Monday and around 300 million in previous days.

"There was a request for 130 million cubic metres. We have supplied that volumes minus 65.3," he told reporters in Moscow.

The amount is equal to that Moscow says Kiev is stealing from European clients further downstream.

Russian Prime Minister Vladimir Putin on Monday gave Gazprom the order to go ahead with the further 20 per cent cut of gas to Ukraine.

Kupriyanov did not say why the figure for European demand was lower than that usually shipped by Gazprom. He said Gazprom was increasing supplies gas deliveries to Europe through Belarus and its Blue-Stream pipeline under the Black Sea.

Alexander Medvedev, the deputy chairman for the gas giant, meanwhile called the crisis "unprecedented" in London while on a tour of European capitals in a lobbying bid to smooth the firms reputation with its clients.

Europe is heavily dependent on Russian natural gas deliveries, with Moscow providing EU nations roughly one-quarter of all gas consumed, 80 per cent of it coming to market from pipelines crossing Ukraine. (dpa)