Liu Zhijun, the Chinese Minister of Railways, has become the latest senior official to be investigated in the country's battle against corruption.

Liu, who heads the country's giant railway system since 2003, is under investigation over alleged "severe violation of discipline," said a Xinhuanet report that quoted the Communist Party of China's (CPC's) discipline watchdog on Saturday.

The Central Commission for Discipline Inspection (CCDI) of the CPC did not give further details, according to Xinhuanet.

Liu, 58, has been removed from his post as the Party chief of the ministry, Xinhuanet quoted the Organization Department of the CPC Central Committee as saying.

Sheng Guangzu, 62, head of the General Administration of Customs (GAC), has reportedly been appointed to replace Liu.

About a month ago, Zhang Jingli, former deputy director of the State Food and Drug Administration, was removed from public office and expelled from the CPC for serious violations.

According to the CCDI and the Ministry of Supervision, Zhang abused his position to receive "a large amount of money" in bribes.

Other high-ranking CPC officials sacked for graft include Kang Rixin, a former head of Chinese nuclear giant China National Nuclear Corporation, and Huang Yao, former chairman of the Guizhou Provincial Committee of the Chinese People's Political Consultative Conference (CPPCC).

A total of 146,517 officials across China were punished for disciplinary violations in 2010, according to the CCDI.

Among the officials, 5,098 were leading at the county level or above and 804 were prosecuted.

Early last month, when addressing a CCDI plenary session, President Hu Jintao stressed that corruption was still a grave concern for the country and vowed that the government would fight it with greater determination and with more force.

Hu had pledged more efforts to be made to investigate "graft in key industries and key posts."

China issued the first ever white paper on its anti-graft efforts last December, expressing its resolve to strengthen the fight against corruption.

Besides penalizing corrupt officials, the country has worked to reform the system and closed loopholes to prevent corruption.

Last December, the CPC Central Committee and the State Council amended an anti-corruption regulation, expanding the original 17 articles to 32 articles and adding more detailed punishments for corrupt officials.

Efforts were made to facilitate public supervision of officials. Discipline inspection organs of the CPC, procuratorates, and government supervisory and audit departments have established tip-off systems with hotlines and websites.

The Supreme People's Court (SPC) said Wednesday that all provincial courts on China's mainland have launched websites to collect tips against corrupt judges, following the launch of a tip-off website by SPC.