BEIJING, Sept. 20 -- China has closed nearly 1.8 million social networking and instant messaging accounts since April this year when it launched a campaign to purge the Internet of obscure contents.

The closed are mainly microblog, WeChat and QQ accounts, said the Cyberspace Administration of China, formerly known as the State Internet Information Office in a statement late Friday. These accounts have been used to release porn information and invite people to solicit prostitution.

China launched the Internet cleansing campaign this April in a bid to eliminate content related to pornography and violence in the cyberspace.

Many of these accounts were shut down by Internet companies such as Sina and Tencent after an internal "self-check," and many were reported by the public. The office also organized special inspections, it said.