Japan will strengthen its oversight of suicidal posts on social media after what was described as the worst case of serial murder targeting young people contemplating taking their own lives happened near Tokyo last year, officials said Friday.

Holding a meeting at the prime minister's office, the government adopted a plan aimed at strengthening internet safety for juveniles and improving education about the risks of using smartphones and other digital devices from early elementary school years.

(The apartment complex in Zama, near Tokyo, where nine dismembered bodies were found in October 2017)

Under the plan, online posts related to suicide will be added to the list of "harmful information" and the government will encourage social networking site operators to delete such contents, as well as promoting "cyber patrols" by private organizations.

The government said it will also create material aimed at raising awareness about internet safety among parents with children, including preschoolers, and inform the public about online filtering systems through schools and kindergartens.

During the meeting, Prime Minister Shinzo Abe, who heads a task force on child education, ordered Cabinet members to "create an environment in which young people can use the internet with security and make utmost efforts toward the realization of the plan."

In the murder case that came to light last October, Takahiro Shiraishi has admitted to killing and dismembering nine people aged between 15 and 26 at his apartment in Zama, Kanagawa Prefecture. The victims posted suicidal thoughts on Twitter before being approached by him online.

In the plan, to be revised every three years in light of the changing online environment, the government referred to the case and said that "new challenges" have emerged.

To better assess internet use among children, the plan said the government will conduct a survey also covering parents with children under 10 years old in addition to those aged between 10 and 17.