"Congregation Leaving the Reformed Church in Nuenen" and "View of the Sea at Scheveningen" were stolen three years ago from the Vincent Van Gogh Museum in Amsterdam, Netherlands.
Although two men were arrested and charged with theft, the whereabouts of the paintings remain a mystery.
FBI Assistant Director Chris Swecker told a news conference it's hard to determine how much art theft costs annually, but it's estimated to be around $6 billion in worldwide losses, CNN reported Wednesday.
For example, he said, artwork expected to sell for $4 million at a recent auction sold for $13 million, he said.
The Top 10 list also includes works by Leonardo da Vinci, Paul Cezanne and Michelangelo. Probably the most recognizable work on the list is Edvard Munch's "The Scream," which was stolen from the Munch Museum in Norway last year.