LONDON—Scotland Yard has seized a pair of old master paintings allegedly exported from Italy illegally, reports the Guardian.

The works, The Departure of the Bucintoro to San Nicolo on the Lido, and The Return of the Bucintoro to the Palazzo Ducale, both by Francesco Guardi and worth about $20 million combined, date from around 1780.

A source at the public prosecutor's office in Rome told the Guardian the works had been seized at the request of Italian authorities.

The works were owned by Mario Crespi, whose family owned the Corriere della Sera newspaper, but were sold to a dealer three years ago.

Italian art export laws are strict, and important works can only leave the country with a special license. It is believed that the provenance for the Guardi works was not made clear when a license was requested.

The works were passed to a British dealer, who apparently sold them to a buyer in the U.S. They were seized before they could leave the country.