Updated

Russia and Ukraine's energy ministers are holding emergency talks in Brussels as Russian gas giant Gazprom threatens to cut off deliveries to Ukraine for lack of payment.

European Union energy spokesperson Anna-Kaisa Itkonen said Monday that the EU's executive Commission will mediate between the sides in an attempt to make sure gas keeps flowing despite the dispute.

The EU imports around 40 percent of its gas from Russia, half via pipelines through conflict-torn Ukraine.

Kiev and Moscow have been embroiled in numerous gas price wars and concerns are mounting that any fresh cuts in Ukraine could again hit European Union supplies.