The Central Commission for Discipline Inspection (CCDI), the Chinese Communist Party's anti-graft and political disciplinary watchdog, made the proclamation amid an investigation into alleged graft surrounding military procurement.

Xi has pursued a tough and sweeping anti-graft campaign since taking power in 2012 and recently declared "overwhelming victory" in the crackdown while vowing to keep up the pressure.

"We must never turn back, slack off or show mercy in our fight against corruption," he told a CCDI meeting on Monday.

In a communique on Wednesday, the CCDI promised "relentless efforts" to implement Xi's call for ruling party officials to constantly check themselves for possible misconduct.

The CCDI also pledged to "focus on political loyalty and political security" and "remove hidden political dangers in a timely manner".

Xi views his anti-corruption drive as a key political achievement, but critics say the campaign has been used to purge his political opponents and does not address the root causes of graft, such as low wages and the unchecked powers of party-appointed state officials.

The ruling party does not open itself to external audits or investigations and critics say the judiciary is not independent.

According to CCDI statistics, the commission investigated 4.7 million officials during the first decade of the campaign.

It echoed Xi's call to focus its efforts in sectors including finance, energy, infrastructure, and healthcare.

(Reporting by Yew Lun Tian; editing by Mark Heinrich)