PHOENIX — A polygamist religious leader who claimed more than 20 spiritual “wives” including 10 underage girls was sentenced to 50 years in prison on Monday for coercing girls as young as 9 years old to submit to criminal sex acts with him and other adults, and for scheming to kidnap them from protective custody.

Samuel Bateman, whose small group was an offshoot of the sect once led by Warren Jeffs, had pleaded guilty to a yearslong scheme to transport girls across state lines for his sex crimes, and later to kidnap some of them from protective custody.

Under the agreement, Bateman pleaded guilty to one count of conspiracy to commit transportation of a minor for sexual activity, which carries a sentence of 10 years to life imprisonment, and one count of conspiracy to commit kidnapping, which is punishable by up to life imprisonment. He was sentenced to 50 years on each count, to be served concurrently.