WASHINGTON — The Federal Bureau of Investigation said Monday that a nationwide operation had led to the arrests over the last few days of 159 men charged with forcing about 105 teenage girls to work as prostitutes. Some of the girls were as young as 13.

The operation was part of a decade-long Justice Department program — the Innocence Lost National Initiative — that is intended to break up child prostitution rings. The program has led to the convictions of 1,350 people for pimping-related offenses, 10 of whom received life sentences, according to the F.B.I.