BEIJING, Oct. 28 (Xinhua) -- China has started this week a three-month campaign on the crackdown of Internet piracy to purify the online atmosphere of copyright protection, officials said.

"The campaign will step up its crackdown on illegal websites which engage in piracy-related activities, and investigate in-depth those serious cases," said an official with the National Copyright Administration.

He said the campaign is especially focusing on online piracy of music, movies, software and books and crack hard on private-run game servers and actions or tools damaging Internet technological protection measures through malice.

The administration has also set some key areas like Beijing, Shanghai, Chongqing, Jilin, Zhejiang, Jiangsu and Anhui to exert more crackdown effort.

China launched a 100-day anti-piracy campaign on July 15. The campaign was jointly run by 10 ministries and national departments, including the Ministry of Public Security, the State Administration of Press and Publication, the National Copyright Administration and the Ministry of Culture.

Since then, China has destroyed nearly 13 million pirated CDs, DVDs and computer software products.