Ukrainian President Volodymyr Zelenskiy on Monday criticised what he said was Slovak Prime Minister Robert Fico's lack of desire to end his country's dependency on Russian natural resources as a "big security issue" for Europe and Slovakia.

The weakness, dependence, and short-sightedness of Slovak Prime Minister Robert Fico's energy policy pose threats to the whole of Europe,” said Ukraine's foreign ministry.

Slovak Prime Minister Robert Fico met Russian President Vladimir Putin in Moscow on Sunday. The premier's trip came a little more than a week before the expiry of a transit contract between Moscow and Ukraine that allows about 15 billion cubic meters of Russian pipeline gas per year to be shipped to a number of European nations.