Political ransom note for stolen Chagall

Curators at the Jewish Museum in New York have a letter claiming responsibility for the theft of a $1m (£690,000) Marc Chagall oil from their walls and offering its safe return only when there is peace between Israelis and Palestinians. Until then, said the letter, the painting stolen in June would be "looked after".

Art is not often stolen for political ends rather than money. Something similar did happen when Edvard Munch's Scream disappeared from Norway's National Gallery in 1994. Anti-abortion activists said they would return the painting only if a film supporting their cause was shown on national TV.

At least in that case, airing the film was a practical option, although the anti-abortionists never had Scream, which police eventually recovered.

But the tiny Jewish museum on Fifth Avenue can hardly hope to speed peace in the Middle East. Investigators say they are convinced that the letter, signed by a previously unheard-of group calling itself the International Committee for Art and Peace, was written by whoever has the picture because of the other details contained in it.

The 8in by 10in oil, Study for 'Over Vitebsk', completed in 1914, shows an old man with a walking stick and beggar's sack, floating over a village. It vanished during a cocktail party at the museum on 8 June and there is a $25,000 (£17,000) reward for its return.

The museum insists that receiving the political ransom note was better than hearing nothing at all. "We are extremely distressed about the missing painting, and this communication gives us hope for the possibility of recovering it," a spokeswoman said.