Corruption is the biggest threat to China's Communist Party, President Xi Jinping said on Monday, in a clear warning that the ruling party is resolved to tackle a long-running problem that is now entrenched in many strata of Chinese society.

More than 200 specialized detention facilities have been built or expanded across China, a CNN investigation finds, as the Chinese leader extends his crackdown beyond the ruling Communist Party to a vast swath of public sectors.

Chinese President Xi Jinping has warned of “catastrophic” risks for the country if there is any let-up in the decade-old anti-corruption crackdown, adding that the fight remained “grave and complex”.