BEIJING, Jan. 6 -- China will intensify efforts to crackdown on crimes committed with unregistered SIM cards.

There are more than 130 million "black cards" in circulation at present, which refer to unregistered phone cards which are used in cell phones or provide wireless Internet services.

This, however, runs contradictory to a regulation passed by the government on Sept. 1, 2013, which mandated that SIM cards must be registered with genuine identities.

China Mobile, the nation's largest wireless service provider, said on Tuesday that up to 16 percent of its users were unregistered, making it the major source of unregistered customers in the country compared to its competitors China Telecom and China Unicom.

The black cards could be used to spread pornographic content, engage in phone or text message scams and even organize terror activities. Without registration, black card users are more difficult to track by police, according to the Industry and Information Technology Ministry.

The Public Security Ministry said that the country reported 157,000 cases involving phone scams and the online sale of user information to third parties in 2014 alone, with 273,000 suspects arrested.

Chinese authorities will accelerate identity confirmation in order to prevent crimes through the year, according to a joint statement issued by the two ministries and the State Administration of Industry and Commerce.