The ruling by a Japanese high court that ordered a woman to return her son to his father in the United States has been finalized, court officials said Monday.

The mother did not appeal the ruling by the Nagoya High Court in central Japan delivered earlier this month that said she failed to comply with an international convention on child abduction and that there was a clear illegality in keeping the American-born son in her custody.

The parents, both Japanese, disputed the custody of their son who was brought to Japan by the mother without the father's consent in 2016.

The Tokyo Family Court had ordered the mother to return the son to the United States based on the 1980 Hague Convention on the Civil Aspects of International Child Abduction.

Since she did not follow the order, the father filed a habeas corpus appeal with the high court's Kanazawa branch.

The high court branch rejected his claim last November, but the Supreme Court in March overturned the ruling and sent the case back to the high court.