China has been given a political promise by Western countries that they will not become havens for corrupt fugitives, a senior official told state television, though he offered no assurances to assuage concerns about mistreatment of suspects.

China has vowed to pursue an overseas search dubbed Operation "Fox Hunt" for corrupt officials and business executives, and their assets, part of President Xi Jinping's war on deep-seated corruption.

It has been pushing for extradition treaties. But Western countries have been reluctant to help, not wanting to send people to a country where rights groups say mistreatment of suspects is a concern.