BRUSSELS, July 28 (UPI) -- A European energy administration agency said Monday the Ukrainian government needs to examine its contractual relationship with Russian energy company Gazprom.
The European Energy Secretariat sent a letter to Ukrainian Energy Minister Yuri Prodan calling for an assessment of the contract between Ukrainian energy company Naftogaz and Gazprom.
Gazprom in June switched Naftogaz over to the new payment scheme because of $4.45 billion in overdue bills.
Russia supplies about a quarter of the European Union's gas needs, though most of those supplies run through the Soviet-era transit network in Ukraine. Debt disputes in 2006 and 2009 prompted Gazprom to cut gas to Ukraine briefly, causing regional energy shortages.
Russia this year offered some concessions to their Ukrainian energy counterparts, though the government in Kiev said it was wary of the Russian intentions. European officials have said the region's energy sector was subject to "political and commercial blackmail."