The country's top anti-graft agency published a confession on Sunday by a former official who returned from the United States after more than 2 1/2 years in hiding.

The agency pledged that there would be no letup in hunting down others overseas.

The 3,400-word confession by Wang Guoqiang, former Party chief in Fengcheng, Liaoning province, was published on the website of the Central Commission for Discipline Inspection, together with a commentary expressing the commission's determination to catch corrupt officials who have left the country.

Wang went to the US on a regular Chinese passport in April 2012, 20 days after he was removed from his post as the top official in Fengcheng. He stayed there for 32 months before returning to China. He was prosecuted shortly afterward.

In his confession, Wang elaborated on the rough conditions of his US stay, describing it as a "nightmare in my life", and he warned anyone who has the idea of sneaking overseas against what he characterized as a "dead end".

"I dared not use my passport, and my wife and I dared not meet our daughter, who was also in the US. If I were allowed to choose again between sitting in jail in China and merely surviving in the US, I would choose the former," Wang said.

"I dared not to go to a hospital when I was sick because I feared my identity would be exposed. I had to rent with other people in case the police came and checked my passport."

Wang turned himself in and arrived in Beijing in December 2014 after he learned China had started a sweeping anti-graft campaign to net those hiding overseas. He was the first official returning of his own accord since the campaign started in late 2012.

In a separate article, the commission criticized the practice of some foreign countries that provide shelter for those involved in corruption cases in the name of protecting human rights.