The BBC reports that “The landscapes, by Mykola Hlushchenko, were lent to the government by the National Art Museum in 2001.
But chemical tests “have shown that both paintings are replicas of Hlushchenko’s works,” said Ukraine’s culture ministry in a statement.
The museum has called for a criminal investigation into the affair.
The disappearance of the paintings was first made public by museum officials on 29 March, prompting tests to verify the claim.
After examining the paintings, experts said, “the nature of the luminescence in the zinc white paint layer, and the degree of drying in selected samples means they were paintings created in the 21st Century”.
Insurers have valued the two originals at about $144,000 (£88,776).
The National Art Museum added it “categorically denies any suggestion and innuendo” that the paintings it lent to the government were not genuine.
Hlushchenko was born in East Ukraine in 1901, and served in the Russian army fighting communists in 1919. After being taken prisoner, he escaped from a camp in Poland, from where he made his way to Germany and enrolled in the Berlin Academy Of Art.
From 1925, he lived in Paris – where he divided his time between painting and working as a Soviet spy.
He is best known for his landscapes, painted in the post-impressionist style, although he also created several still lifes, nudes and portraits – including those of French writers Henri Barbusse and Victor Margueritte.
Hlushchenko returned to his homeland in 1936, where he taught art for several years, before moving to Moscow on the eve of World War II, where he remained until his death in 1971.”
Image above: Mykola Hlushchenko ‘Boats’, 1975 watercolor