Russia said on Monday that the situation with European countries that buy its gas through a transit deal via Ukraine is very complicated and needs more attention, after talks between President Vladimir Putin and Slovak Prime Minister Robert Fico.

Russian President Vladimir Putin met Slovak Prime Minister Robert Fico in the Kremlin on Sunday, a rare visit by a European Union leader to Moscow as a contract allowing for Russian gas to transit through Ukraine nears expiry.

A major contract governing the transit of Russian gas through Ukraine will come to end on January 1, with significant implications for Moscow’s exports to some European Union countries. “The end of the transit contract will mark an important shift because gas via Ukraine governed by the contract currently accounts for half of Russia’s remaining