Russia has resumed gas supplies to Europe through Ukraine after agreeing to a EU-brokered deal.

Gazprom, Russia's state-run energy provider, said on Tuesday it had sent its first 76 million cubic metres of gas through the pipelines at 10am (0700 GMT).

The resumption ends a bitter gas row between Russia and Ukraine, that left much of Europe shivering in freezing winter.

However, experts say it could take between 24 and 36 hours for the gas pumped via Ukraine to reach Europe, where 15 countries have been left without heating since exports were cut off last Wednesday.

Under the deal, that had to be signed twice in two days, 25 international observers from the European Union, Ukraine and Russia will supervise gas flows at five transit points in Ukraine and another three stations in Slovakia and Romania.

The European Commission welcomed Moscow's announcement and said its monitors in Ukraine would verify the current situation.

Damaging dispute

On January 1, Russia cut off all shipments to Ukraine after the two countries failed to renew a gas agreement for 2009 and Moscow accused Kiev of stealing gas destined to its European clients.

Ukraine, an ex-Soviet state with pro-Western leaders, has also angered the Kremlin in the past months because of its attempts to join Nato.

The dispute damaged the reputation of both countries as reliable energy partners and prompted Europe to search once again for alternative energy sources and routes.

Russia supplies an average of 350 million cubic metres of gas to the 27-nation block during the winter season.

The European Union relies on Russia for about one quarter of all the natural gas it needs, and 80 per cent of those volumes arrives via pipelines crossing Ukraine.