Slovakia has confirmed that gas is flowing into its system from Ukraine as the Velke Kapusany transit point on the border has opened.
Slovakia is the first EU country to receive gas from Russia via Ukraine again, after being cut off from the deliveries, on which it depends for 98% of its supplies, for two weeks.
Russia's state-controlled gas monopoly, Gazprom, earlier resumed exporting supplies to Europe via Ukraine.
The move followed the signing of a new 10-year gas contract and late-night talks between the Ukrainian Prime Minister, Yulia Tymoshenko, and Gazprom executives.
The EU said it would not consider the crisis over until its monitors verified that gas had reached its borders.
