BEIJING, June 13 (Xinhua) -- China's Telecom operators have intensified their crackdown on spam short messages as mobile phone users complain of getting up to 641 million junk texts a day.

    The three main mobile network operators, namely the China Mobile, China Telecom and China Unicom, on Friday agreed to launch a joint platform in the next few weeks to trace the sources of junk messages.

    They also signed an agreement to deal with inter-network spam messages, Saturday's China Daily reported.

    The three mobile network operators will limit the number of messages that can be sent from a phone number in an hour to 200, and in a day to 1,000 on weekdays. The numbers for weekends will be 500 an hour and 2,000 a day, according to the agreement.

    Spams have become a nuisance as hundreds of small wireless service providers keep sending advertising messages to subscribers that cover items from fake financial documents to weapons.

    Last year, a survey conducted by QQ.com, one of China's largest news portals, showed 98.1 percent of people received spams every day, with about 20 percent getting three to five in 24 hours.

    China Mobile, the country's largest telecom operator, would start a national campaign to promote anti-spam software in its user base, Lu Wenchang, company deputy marketing manager, said on Friday.

    Lu was addressing a conference, organized by the Ministry of Industry and Information Technology's China Academy of Telecommunication Research.

    China Telecom and China Unicom said they would soon launch an anti-spam firewall. "We need to have a long-term scheme to curb spams," Zhu Zhengwu, China Telecom deputy manager, said. China Telecom is developing anti-spam software, which is being tried out in 31 provinces.

    Public anger against spams climaxed in March last year after CCTV reported that Focus Media Wireless, mobile advertising subsidiary of Focus Media, sent more than 100 million spams to subscribers every day.

    The government decided to crack down immediately on those sending junks. But most of its efforts failed because it is difficult to differentiate spam senders from ordinary cell-phone users.