Internet service providers should report to police all people who post messages on suicide Web sites, a National Police Agency security panel recommended Thursday.

Japan has seen a spate of group suicides by people who met through such Web sites.

The NPA plans to ask ISPs through an industry group to disclose the names, addresses and other personal information of users. It hopes to have the system in place by summer, NPA officials said.

ISPs are obligated to protect the confidentiality of all Net-based communications. They stipulate in their guidelines that they will only disclose personal information in emergencies.

Some ISPs have voluntarily turned over users' personal information in the past.

But under the recommendation, ISPs would be asked to release personal data on users who have posted messages containing individual or group suicide plans, or murder plots.

Last year, 19 groups are known to have organized suicides via the Internet, resulting in the deaths of 55 people, the NPA said. In 2003, 12 groups met via such sites, leading to 34 deaths.

In the first three months of 2005, there already have been 20 cases, with 54 people dead.

The NPA said there has also been an increase in the number of murder plots and threats posted on the Web.

To track down the posters of the messages, police usually have to get court warrants ordering disclosure from the holders of the information. But as suicide is not a crime in Japan, such warrants are unobtainable, the NPA said.

Similarly, police sometimes cannot obtain court warrants in response to murder plots or threats if they only say, for example, that an unspecified person, such as a "Tokyo child," is going to be killed.

In one case, the swift disclosure of information saved a woman who tried to commit suicide, the panel said.