Moscow (AFP) - Russia's Gazprom on Thursday started supplying gas directly to the rebel-controlled area in east Ukraine after pro-Moscow separatist leaders said Kiev had cut supplies, the company's chief said.

"From 1600 (1300 GMT) on February 19, Gazprom is supplying gas to Ukraine including through the Prokhorovka and Platovo gas metering stations to an amount of 12 million cubic metres per 24 hours," said Alexei Miller, quoted by RIA Novosti news agency.

Prokhorovka is on the border of Russia and the rebel-controlled Lugansk region, while Platovo is on the border of Russia and the Donetsk region.

Miller said the deliveries were being made according to the "current sale-and-purchase contract between Gazprom and Ukraine's Naftogaz," without giving any details.

The leader of the separatists' self-proclaimed Lugansk people's republic, Gennady Tsypkalov, confirmed to RIA Novosti that an agreement had been reached with Russia.

Russian Prime Minister Dmitry Medvedev said in a government meeting earlier Thursday Russia could deliver "humanitarian aid in the form of gas supplies" to the separatist-controlled territories and ordered the energy ministry to coordinate this with Gazprom.

Ukraine's pro-Russian separatists said Kiev had ceased gas supplies suddenly, without warning. They said they wanted access to Russian gas.

Naftogaz, Ukraine's national gas company, confirmed the cut-off, and said it was due to pipeline damage caused by fighting.

"Resuming supplies is impossible because of the ongoing fighting" which was stopping repair teams from safely carrying out the necessary work, the company said in a statement.

Naftogaz's chairman Andriy Kobolev later said Gazprom was billing his company for the gas being provided, but Naftogaz was refusing to pay because it had no control over the territory where "terrorists" had damaged the pipes nor any way to check how much gas was supplied.

The Ukrainian gas pipeline operator Ukrtransgaz said it would start repairs as soon as the fighting ended.