Armed men burst into the headquarters of Ukraine’s energy firm Naftogaz on Wednesday in what the security service said was part of a criminal inquiry.

An abrupt rise in Russian gas prices will undermine Ukraine’s economic and energy security and leave some enterprises on the brink of insolvency.

The EU raised the stakes with Ukraine and Russia on Wednesday by threatening to ditch them as gas suppliers and to promote court action against them.

Russian gas delivered into Ukraine’s pipelines to end an embargo on Europe cannot be transported onwards, officials said on Tuesday.

Russia and Ukraine held talks over a solution to the escalating gas dispute, it was reported on Thursday.

Russia halts gas supplies to the Balkans, Turkey and south-eastern Europe, while flows to Austria drop by 90% in a deepening price row

Russian gas monopoly Gazprom accused the Ukraine on Wednesday of planning to siphon off gas that Russia transits through Ukrainian territory to the European Union, as a payment…