BEIJING, Oct. 29  -- China's top prosecutor on Wednesday pledged efforts to stem illegally granting parole or shortening prison terms.

Starting from March this year, prosecuting authorities strengthened supervision on changes of sentences for those involved in post-related, financial and gang-related crimes.

Until the end of September, Chinese prosecutors proposed re-jailing 800 criminals who were serving their sentence outside of jail by using their connections or bribery to lighten their penalties, said Procurator-General Cao Jianming when delivering a report at a bimonthly session of the Standing Committee of the National People's Congress.

A total of 129 state staff involved in these cases were investigated for suspected falsification, bribery and practising favoritism, Cao said.

The public has been complaining that powerful or rich people who commit crimes were found to have their sentence reduced, get parole or serving a jail term out of prison.

Cao said prosecutors of various levels should strictly regulate the work of investigation, supervision and public prosecution, prevent cases involving unjust, falsely and wrong charges.

He called on the country's procuratorial staff to adhere to professional ethics and the rule of law and prudently practice their duties in supervising criminal procedures.

He also said supervision from the public would be strengthened.