Pop queen Madonna is living in fear after allegedly receiving death threats from the Russian mafia. The HOLIDAY star, currently touring Europe, is so terrified that she refuses to leave her hotel room unless she has to go to a performance. And all plans for sightseeing and shopping were cancelled after a Czech newspaper reported that crime bosses threatened to kill her and her two children. A source says, "She is unbelievably nervous and worried about performing in Moscow next week. Because of that she wants to get home as soon as possible and doesn't want to be away a minute more than is necessary."