(JTA) — A masked gunman stole $53 million worth of diamonds and jewels owned by Israeli billionaire Lev Leviev from an exhibition at a luxury resort in Cannes.

The masked gunman threatened the exhibition staff and visitors at the Carlton Hotel on Sunday afternoon, filled a briefcase with the jewels and fled, according to reports.

It could be among the largest jewelry heists in France if the value of the jewels is as reported, according to the BBC.

Leviev, 57, a Soviet-born Israeli Jewish businessman and philanthropist, owns diamond mines in Russia and Africa.

Two large jewelry heists occurred in Cannes in May during the popular Cannes Film Festival.