Russia could resume gas flow to Europe Friday: Gazprom chief

"We are counting on the protocol being signed today... and then we will literally immediately resume delivery," the agency quoted Gazprom chief executive Alexei Miller as saying.

Miller had earlier vowed to immediately resume gas shipments to Europe once independent monitors were in place to guarantee the flow to EU markets.

The first observers tasked with monitoring flows of Russian gas in Ukraine are en route for Kiev and due to arrive at 1200 GMT, a European Commission spokeswoman was quoted as saying on Friday.

It would take at least three days for Russian gas supplies, currently suspended, to return to Europe, the European Commission also said.

European Union officials started critical talks on Thursday with feuding Russian and Ukrainian gas executives to work out a way to send monitors to ensure that gas flows back into trans-European pipelines.

International observers will check how much gas is being piped from Russia to Ukraine -- a major transit route for supplies in Europe -- at a pumping station "several hundred kilometers" from their common border.

Russia is the world's biggest natural gas producer and provides about one-quarter of the gas used in the European Union, or about 40 percent of the gas the bloc imports. About 80 percent of those imports pass though Ukraine.

Russia cut off all supplies for Ukraine's domestic market on Jan. 1 and then halted all supplies to the country, even those intended for Europe, on Wednesday.

Moscow claims Ukraine has been siphoning off gas meant for Europe.