Berlin : Some 1,500 works by artists like Picasso, Nolde and Matisse believed to be stolen by the Nazis in the 1930s were found at an elderly man's apartment in the German city of Munich, media reports said.
The artworks were found in 2011, but the discovery was kept quiet until Focus magazine published a story about the find Sunday.
The story has sparked speculation in the German media that more looted works may be awaiting discovery.
The works, which are estimated to be worth around 1 billion euros, were found amid food remains, cans and trash in the home of 80-year-old Cornelius Gurlitt.
Gurlitt put Max Beckmann's "Lion Tamer, Circus" up for sale at auction months after the investigation started.
The government has been monitoring the investigation, which is being handled by prosecutors in Augsburg, for months and offered to bring in experts to examine the works, Chancellor's Office spokesman Steffen Seibert said Monday.
Officials and investigators have worked for decades to track down the works of art stolen by Adolf Hitler's Nazi regime and return them to their rightful owners.