BEIJING - Baidu, China's top search engine, is facing punishment over forums containing pornography, libelous posts and adverts for unlicensed hospitals.

The State Internet Information Office summoned Baidu executives for a grilling on Friday and ordered them to immediately remove the contents. It also ordered Internet regulators in Beijing, where Baidu is headquartered, to punish the company.

The State Internet Information Office has been flooded with public complaints about Baidu, it said in a statement on Saturday. The complaints also claimed Baidu had leaked users' personal information.

"In addition, some search results on Baidu are not impartial or objective, and its news channel has spread harmful information involving violence and terrorism," according to the statement.

It is not yet clear what kind of punishment will be given, but Baidu was fined more than 210,000 yuan (about $33,800) in March last year for carrying online publications without a permit and uploading pornographic novels onto its app.

Baidu principals were cited by the State Internet Information Office as saying the firm has "fully realized the severe inadequacies in its management and the resulting negative social impact."

Baidu users have complained recently about the amount of advertising for dodgy medical services on its health forums.

Responding to that criticism on its Weibo microblog on Saturday, Baidu said it "is reviewing its decision-making and approval procedures so as to fix the problem at the source."