Hitler ordered the "action team" to follow troops

Adolf Hitler ordered a music "action team" - M-Aktion - to confiscate and catalogue any instruments of importance, which were then sent to Berlin.

The team followed German troops around Europe, moving in on the homes of those who had fled the Nazis' advance or who were taken to concentration camps.

"I used to play a wonderful Italian Gagliano violin," said Francis Akos, violinist with the Chicago Symphony Orchestra, who won the instrument in 1939.

But, as a Jew, he was sent to a Nazi concentration camp at the outbreak of the war.

'Disappeared'

"When I came back... I tried to find my friends," said Akos, 79.

"None of them survived the war. And their instruments disappeared somewhere, too. Everything was gone."

Experts say looted instruments could be harder to track down than works of art, which are more easy to identify and are more likely to have associated documents.

Many survivors and families of those whose art was looted or sold under the duress during the war have pressed for compensation or the return of their works, with some success.