BEIJING, Sept. 22 (Xinhua) -- Chinese authorities have closed over 4,000 websites and accounts during a three-month clean-up campaign targeting harmful information in online literature works.

The campaign was jointly launched by the National Office Against Pornographic and Illegal Publications and the State Administration of Press and Publication in May.

As of the end of August, authorities nationwide have amended over 120 relevant violations and ordered 230 enterprises to rectify irregularities, removing or filtering more than 147,000 pieces of harmful information, according to a statement by the two agencies.

The campaign, targeting content in online novels that spread improper values, vulgarity or obscenity as well as those involving copyright infringement, included measures such as relevant websites' self-checks, authorities' inspections and criminal investigations.

The statement said that such measures will be intensified in the future to ensure a healthy and clean online literature environment.