Russian gas exporter Gazprom and its Ukrainian counterpart Naftogaz on Monday filed competing lawsuits at the Stockholm arbitration court to try to recover massive sums of money from each other.
Gazprom said earlier on Monday that Ukraine had failed to pay $1.95 billion of its gas debts by a 10 a.m. deadline and would now have to pay up front for deliveries. The company will now try to recoup Kiev's total gas debt of $4.5 billion in Stockholm.
Naftogaz, meanwhile, hopes to be awarded $6 billion in what it said were overpayments to Russian exporter Gazprom.
Naftogaz said in a statement it was also demanding a "fair and market price" for natural gas supplies from Gazprom, which has also restricted supplies to Kiev over the debt.