Japan repatriated 423 foreign prisoners over the last 16 years under an international treaty designed to help rehabilitate and reintegrate convicted criminals, Justice Ministry officials said Tuesday.

Japan is a signatory to the Convention on the Transfer of Sentenced Persons along with members of the Council of Europe and the United States. A related domestic law was put into force in June 2003.

It has signed separate bilateral treaties with Thailand, Brazil and Iran, which are not members of the convention, and is negotiating similar agreements with China and Vietnam.