China has probed about 700 phone services firms and closed 97 phone sex lines as part of a nation-wide campaign against Internet pornography, the state media reported on Saturday.

China has carried out a national campaign to crack down on phone sex services starting July 2004.

Another 79 phone sex services advertising in newspapers or leaflets were punished, and suspects in Jilin and Hubei provinces were arrested for offering overseas phone sex services, Xinhua news agency quoted officials from the Ministry of Information Industry as saying.

Currently, China has 659 phone service stations with 15,000 employees. In 2003, the total revenue of phone services reached 1.57 billion yuan ($ 189 million), government figures show.

"With the rapid development of the paid call service market in China, some lawbreakers make use of this form to spread obscene information and even conduct prostitution," Minister of Information Industry Wang Xudong said.

"This depraves social morals, and especially brings great harm to the country's young minds," Wang said, adding that the
move would clean up the country's paid call service and ensure a wholesome development of the market.

Earlier this week, police said they have closed down the country's biggest porn Web site and arrested 12 people who ran it.