If Moscow carries out a threat to sanction Ukrainian energy firm Naftogaz, one of the last functioning Russian gas supply routes to Europe could be shut, exacerbating the energy crisis just as the crucial winter heating season begins. Naftogaz initiated a new arbitration proceeding against Gazprom (GAZP.MM) earlier this month, saying the Russian company has not paid transit fees for sending its gas to Europe via pipelines that cross Ukraine. Gazprom this week rejected all the claims , adding that Russia may introduce sanctions against Naftogaz in the case that it further pursues the matter. Such sanctions would prohibit Gazprom from paying Ukraine transit fees, which analysts say could end Russian gas flows to Europe via the country. Yuriy Vitrenko, chief executive of […]