Government agencies in China launched a major crackdown on Monday on websites they say spread pornography, a crackdown that included popular search engines Google and Baidu.

The aim of the one-month campaign is to "purify the internet's cultural environment and protect the healthy development of minors," according to a statement issued by the country's State Council and six other government agencies. The statement was published through the official Xinhua News Agency.

The China Internet Illegal Information Reporting Centre said it found 19 websites that provide content — including links, pictures, text and video — that it deems inappropriate for young people.

Included among the sites were Google, the world's most popular search engine and Baidu, China's most popular search engine, as well as web portals popular in China such as Sina and Sohu.

The government statement said the violators would be severely punished, but did not give details. Pornography is illegal in China but police have difficulty blocking websites based abroad.

A Google spokeswoman in China, Cui Jin, defended the site's operations, saying that as a search engine it does not generate any pornographic content and obeys Chinese law.

"If we find any violation, we will take action. So far, I haven't seen any examples of violations," Cui said.

China's central government has traditionally kept a tight rein on news and media available online, a task that has become more difficult as its population continues to turn to the internet as a source of information. China has more than 250 million internet users, making it the world's biggest internet market by population.

The country loosened some of its internet restrictions during the 2008 Summer Olympics but continues to block foreign websites when material appears that it considers sensitive or political.

Most recently, the New York Times' website was blocked on Dec. 19 and remained so for a couple of days.