Much of the art stolen by Nazis has already been returned to its owners
Jewish groups and representatives of 49 countries are gathering in Prague for talks on returning art and possessions stolen by the Nazis.
The five-day conference in the Czech capital will also aim to increase Holocaust awareness and education.
The Nazis stole an estimated 650,000 religious items and works of art from European Jews during World War II.
While much of the art been returned, a great deal remains in museums and private collections.
The BBC's Rob Cameron in Prague says there has often been considerable reluctance on the part of those in possession of the looted art to return it.
Steps have been taken in countries such as Austria to make it easier for owners to claim back looted art.
But the US Special Envoy for Holocaust Issues, Christian Kennedy, attending the conference, said many central and eastern European countries had not yet found a way to implement a restitution process.
He said any such process would have to be consistent with national law while also ensuring non-citizens seeking to reclaim property were given equal treatment.
Delegates from the 49 states will be asked what progress they have made in returning looted Jewish property since the 1998 conference in Washington.
That meeting introduced ground-breaking principles for dealing with such items.
The Prague conference, the last major event of the Czech Republic's European Union presidency, is aimed at reinvigorating that process, says our correspondent.