More than 20 countries have agreed to updated guidelines on Nazi-looted art, which aim to strengthen the 1998 Washington Principles on Nazi-Confiscated Art.

Under pressure from Holocaust survivor groups and Jewish community organizations, Christies has canceled future auctions of the Heidi Horten jewelry collection, which was acquired through Jewish persecution.

The Metropolitan Museum of Art is taking steps to police its collection for stolen and looted art and artifacts.