The death toll in a fire at an overcrowded budget hotel in the French capital climbed to 21, as investigators continued their probe into the cause, police said Saturday. Rescue workers sifting through the debris from the fire at the Paris Opera hotel found the body of a woman on Friday night, raising the death toll from at least 20 to 21, police headquarters said. The victims in the pre-dawn Friday fire included 10 children. Of the 53 injured, 11 were seriously hurt and treated in hospitals. The fire is thought to have started in a breakfast room at 2:20 a.m. (0020GMT) Friday. It quickly engulfed all floors of the hotel, with smoke and flames sweeping up the single stairwell. With only one exit and no way downstairs, guests were trapped. Many threw themselves from windows. Investigators were probing the cause of the fire, the worst such blaze in recent years in Paris.