SHANGHAI, Dec. 2(AP) -- China will soon require all mobile phone users to register with telecom providers or face a cutoff in service, state media reported Friday.

The new rule, announced by the Ministry of Information Industry, is part of a crackdown on telephone fraud and illegal text-messaging practices, and the country's thriving trade in counterfeit and otherwise illegally obtained mobile phones.

Many Chinese mobile phone users already are registered with major telecoms companies such as China Mobile and China Unicom. But a large share use prepaid phone cards and buy the SIM (subscriber identity module) device that activates the phone without any form of registration.

Implementation of the new requirement is expected to begin by the end of the year, with customers having to comply within six months or lose their phone services, the state-run newspaper China Daily reported.

Subscribers must present their identity cards in order to register, it said.

"It's unfair if we require only new mobile phone users to register and ignore existing customers," the report quoted Chen Yuping, a senior official at the ministry's China Academy of Telecommunication Research, as saying.

"More important, the registration mechanism loses its effectiveness," Chen said.

Up to 200 million of China's 377 million mobile phone subscribers use prepaid cards, the report said.

The new requirement is expected to help authorities control advertising by short-message systems, fraud, and mobile phone pornography, it said.

Documents posted on the Ministry of Information Industry's Web site outlined a broad campaign aimed at curbing illegal trade in counterfeit telephones and cracking down on the country's huge, unauthorized secondhand phone industry.