A painting by a Swedish artist which he says was made with ashes from a former Nazi concentration camp has been displayed in a gallery in Sweden, BBC News reported.

Artist Carl Michael von Hausswolff said that he stole the ashes from the Majdanek camp during a visit in 1989.

The camp, now a museum in Poland, has called the alleged theft an "unimaginably barbaric act".

The artist said the ashes were mixed with water and used to paint a series of grey streaks in the small painting.

Museum officials have said that the painting may be an artistic provocation but it deserves only condemnation.