Delegates from 44 countries meeting in Washington, have agreed to set up a central registry on art looted by the Nazis which could be established on the Internet.

Nazis stole billions of dollars of art from Jews

The international conference was designed to get nations, museums and individuals to re-examine their collections in an unprecedented post-World War II search.

Missing paintings include works by old masters such as Picasso and Cezanne.

Russia took immediate action, handing over a list of several hundred works of art taken from Austrian Jews which was distributed to various art galleries and museums in Austria.

On Tuesday, Moscow said it would try to identify and return the art looted by the Nazis and subsequently plundered by Stalin's troops as "reparations" for Germany's wartime assault.

Germany also announced that any work now owned by the government which had been taken from a Holocaust victim, could be returned to the survivors or their successors.

But our correspondent Nick Bryant says there are fears in the art world that the guidelines could lead to a slump in the auction market, by creating greater uncertainty amongst buyers.

'Every museum has Nazi loot'

The total value of Holocaust era assets is not known. But Ronald Lauder, of the Museum of Modern Art in New York, estimates 110,000 pieces of art worth $10 billion to $30bn are still missing.

Mr Lauder, who heads the World Jewish Congress's art recovery commission, says every institution, art museum and private collection has some of these missing works.

Stuart Eizenstat, head of the US delegation which organised the conference, said the guidelines were not legally binding, but represented a moral commitment to trace and return stolen art.

"The art world will never be the same in the way it deals with Nazi-confiscated art," Mr Eizenstat added.

"From now on, the sale, purchase, exchange and display of art from this period will be addressed with greater sensitivity and a higher international standard of responsibility."