Russian gas supplies to the European Union (EU) states via Ukraine ended on Wednesday after Ukraine's gas transit operator Naftogaz refused to renew its latest five-year transit deal with Russia's Gazprom.

Ukraine's decision to turn off the taps keeping Russian gas flowing via its territory to Europe has already sown trouble in the continent's east, with Moldova declaring a state of emergency and Slovakia threatening Kyiv with retaliation.

By Vladimir Soldatkin and Dan Peleschuk MOSCOW/KYIV (Reuters) -Russian natural gas exports via Soviet-era pipelines running through Ukraine to Europe were halted in the early hours of New Year's Day as a transit deal expired and warring Moscow and Kyiv have failed to reach an agreement to continue the flows.