The China National Petroleum Corporation (CNPC), Asia's largest oil and gas producer, confirmed on Thursday that it has decided to remove its four senior executives under investigation for "serious violations of discipline" from their posts.

The four executives are Wang Yongchun, deputy general manager of the CNPC; Li Hualin, deputy general manager of the CNPC; Ran Xinquan, vice president of PetroChina Company Ltd.; and Wang Daofu, chief geologist of PetroChina.

The CNPC's Communist Party of China (CPC) committee said the four people have been relieved of Party-related posts and corporate administrative posts, and their job titles with CNPC's joint-stock and listed subsidiaries will be removed following due procedures.

The CNPC has appointed Liu Hongbin, Wen Qingshan, Zhao Zhengzhang and Zhao Wenzhi to take over their positions.

On Monday, the Commission for Discipline Inspection of the CPC Central Committee confirmed that then-CNPC deputy general manager Wang Yongchun is being investigated over suspected "serious violations of discipline."

The State-owned Assets Supervision and Administration Commission on Tuesday confirmed the other three are being investigated under the same allegation.