Polish researchers said they have discovered mass graves at Sobibor, a death camp in eastern Poland that was razed by the Nazis after inmates staged an uprising.
Seven mass graves and the sites where several buildings stood were found, said Andrzej Kola, an archeology professor supervising what he said was the first thorough study of the former camp. Some 250,000 people, most of them Jews, are believed to have died at the site.
The Nazis evacuated the camp in 1943 after an uprising in which more than 300 Jews escaped. About 50 of the escapees survived World War II.