BEIJING -- A multi-department circular on fighting telecom and Internet fraud was issued on Friday, tightening preventive measures and ordering police to hunt down perpetrators.

The circular, jointly issued by the Supreme People's Court, Supreme People's Procuratorate, Ministry of Public Security, Ministry of Industry and Information Technology, the People's Bank of China, and the China Banking Regulatory Commission, made it obligatory for telephone accounts to be registered using real identity information.

All telecom service providers must make sure that 100 percent of the country's telephone accounts are registered under real identities by the end of this year and suspend the use of accounts without real identity registration, it said.

In the banking sector, the circular prolongs the period of time needed for money to be transferred from an account holder to another via Automatic Teller Machine (ATM) to 24 hours. The new measure will go into effect on Dec 1.

In telecom fraud, swindlers often trick victims into transferring money to their accounts via ATM. In some cases, money in transfer can be frozen if victims call the police in time.

The circular vowed to crack down on leaking and trade of personal information. It ordered law enforcement to delete, monitor and block Trojan horse and other malicious software and personal information disseminated online.

Websites or Internet accounts found to be at fault will be shut down, and perpetrators may be subject to criminal penalties, it added.

The circular also called for measures to sever distribution channels of software that alters caller ID display, often used in telecom scams, and urged timely interception of calls made using such software.

Police should launch an offensive against scammers and "destroy a number of criminal groups," as well as coordinate with courts and procuratorates to rein in the spread of telecom and Internet fraud, the circular said.

It also urged scammers to turn themselves in by Oct 31, and said whoever fails to do so will be sternly punished.