The Supreme Court says an American mother illegally moved her son from Chile to the United States during a custody dispute with the boy's British father.

The high court on Monday said an international child custody treaty demands that the child goes back to the South American country.

The parents separated in Chile, and the courts there had granted the father visitation rights. But the mother fled with the boy to Texas and filed for divorce. She asked the court there to change the father's visitation rights. The father asked that the boy be returned to Chile.

The justices say the mother can argue in the lower courts that her safety may be at risk in Chile. That is an exception that can overrule the requirement that the child be returned to Chile.