Zhou Yuan, vice chairman of Sinopec, has taken Chen's responsibility before a new chairman is elected, said the statement.

The State-owned Assets Supervision and Administration Commission said in statement on its Web site on Friday that Chen also resigned from the posts of general manager and secretary of the Communist Party Committee of China Petrochemical Corporation, Sinopec's parent company, for personal reasons.

The commission did not specify the reasons behind Chen's resignation.

It said Su Shulin replaced Chen as the general manager and Party secretary of the parent company.

In November 2006 Su resigned from the post of senior vice president of PetroChina Co. Ltd. and was later appointed a senior government official of the northeastern province of Liaoning.