President Xi Jinping urged disciplinary officials on Tuesday to take a zero-tolerance stance on corruption, saying "strong remedies must be continuously used to cure the illness."
He said anti-graft work last year was effective and the campaign is "a matter of life or death" for the Party and the nation. The central government has adopted a "zero tolerance" attitude to combat corrupt officials.
Xi made the remarks at the Fifth Plenary Session of the 18th Central Commission for Discipline Inspection of the Communist Party of China.
Meanwhile, the top anti-graft watchdog has sent more inspectors to carry out five rounds of inspections in key regions and areas, as well as central administrations and authorities, to collect valuable tipoffs about corruption, he said.
A number of high-ranking officials have been placed under investigation.
They include four former top leaders - Zhou Yongkang, the country's former security chief; Xu Caihou, former vice-chairman of the Central Military Commission; Ling Jihua, former minister of the United Front Work Department of the Communist Party of China Central Committee; and Su Rong, former deputy chairman of the National Committee of the Chinese People's Political Consultative Conference.
"The investigation of such senior officials fully reflects the Party's courage to face the problems and correct the mistakes," Xi said, adding that the Party will constantly "purify itself" and make innovations in the fight against graft.
However, he warned that the battle has not yet been won.
Corruption has not vanished, he said, adding that although mechanisms have been put in place, they are not perfect. As a result, temptations remain.
Efforts to rectify the four undesirable work styles of formalism, bureaucratism, hedonism and extravagance, which were listed by the Party in its "mass-line" campaign that ended in October, should continue, Xi said.
"Our determination to use strong remedies to cure illness will not change. Our courage to rid our bones of poison will not diminish. We will also continue to hold high the sharp sword of countercorruption," Xi said.
Disciplinary inspection authorities will also exert strong pressure to combat corrupt officials.
"We should fight corruption with firm resolve, like using strong medicine to cure a serious illness, and once we discover clues to corruption, we will thoroughly investigate them, without lenient punishment."
The central government will also deepen the mechanism for reforming disciplinary inspection authorities, and enhance supervision of anti-graft authorities to improve work efficiency.
Hong Daode, a law professor at China University of Political Science and Law, said, "The speech delivered by President Xi reflects the Party's courage and determination to fight corruption."