The European Commission called on Russian gas monopoly Gazprom and Ukraine on Tuesday to resolve speedily differences over payment for gas delivered to the former Soviet republic, according to Reuters.

"The Commission was informed by Gazprom about a problem of payments for gas delivered to Ukraine and a possibility to reduce gas deliveries to Ukraine if no satisfactory solution was found," the European Union executive said.

"The Commission urges to find a speedy settlement for this issue," it said in a statement.

The Commission noted that Gazprom had promised to honour all existing gas supply commitments to European companies.