WASHINGTON (Reuters) - The Supreme Court on Tuesday ruled for the American father in an unusual international custody dispute over a girl who has been living outside the country under a court order.

By a 9-0 vote, the court ruled in favor of Jeffrey Chafin, a U.S. Army sergeant who challenged the awarding of his daughter Eris to her mother, Lynne Chafin, a Scottish national.

The 11th U.S. Circuit Court of Appeals had dismissed Jeffrey Chafin's appeal, saying the issue was moot because the girl by then was already in Scotland and beyond its control.

(Reporting by Jonathan Stempel; Editing by Howard Goller and Bill Trott)