Moscow announced Thursday that Russia will sue Ukraine in the London Court of International Arbitration over failing to pay a $3 billion debt, International Business Times reports. Kiev officially defaulted on the debt on Friday. Russia loaned Ukraine $3 billion in 2013 while ousted pro-Russian leader Viktor Yanukovych was still president. Ukraine’s current government alleges Yaukovych fled the country with the money. Kiev and Moscow have failed to agree on a way to restructure the debt.