BEIJING: China's top most-wanted corruption suspect returned to China from the United States on Wednesday and turned herself in, the ruling Communist Party's graft watchdog said, as the country pursues an overseas search for corrupt officials.

Yang Xiuzhu, a former deputy director of Wenzhou's construction bureau in the booming eastern province of Zhejiang, surrendered to Chinese authorities after spending 13 years in hiding overseas, the Central Commission for Discipline Inspection said in a statement on its website.

In April last year, China published a list of 100 of its most wanted corruption suspects who had been targeted with an Interpol red notice, many living in the United States, Canada and Australia.

Yang was ranked number one on the list and is the 37th fugitive to return so far, the commission said.

It did not provide an explanation for why she had turned herself in, but her brother, regional official Yang Jinjun, also wanted for corruption, was sent back to China in September 2015, the first time Beijing succeeded in bringing back a suspect from the United States.

Chinese Foreign Ministry spokesman Geng Shuang said her return was an important result for Sino-US anti-corruption cooperation and expressed thanks.

The international community was increasingly on the same page when it came to having zero tolerance towards corruption, Geng told a daily news briefing.

Yang fled China in April 2003 after authorities began investigating her alleged involvement in criminal activities, it added, and sought political asylum in France, the Netherlands and the United States.

Chinese state television showed live footage of a bespectacled Yang, dressed in a grey padded jacket and dark trousers, being led off an American Airlines plane and going through immigration, escorted by two guards.

China has pursued an overseas search dubbed Operation Fox Hunt for corrupt officials and business executives who have fled abroad with 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 back to a country where rights groups say mistreatment of suspects is a concern.

A US State Department spokeswoman said last month the United States was not negotiating an extradition treaty with China but fugitives could be returned to other countries without one "within the bounds and protections afforded by our Constitution and laws".

Yang, accused of stealing $39 million while deputy mayor of Wenzhou, told Reuters last year she was innocent and called the most-wanted list a political document targeting enemies of the current regime rather than a roster of criminals.