Japan will develop its first-ever computer virus by next March as a defense measure against cyberattacks, sources have said.

The Defense Ministry is considering malware that can break into a computer system, hoping such a computer virus could work as a deterrent against cyberattacks, the sources said Monday.

The government has said it is looking to enhance its defense capabilities beyond the ground, marine and air domains to address security challenges in new areas such as cyberspace and outer space amid technological advances in recent years.

Japan lags behind other countries in addressing the threat of cyberattacks. It plans to increase the number of personnel in its cyberspace unit to 220 from 150, compared with 6,200 in the United States, 7,000 in North Korea and 130,000 in China, according to the ministry.

The ministry has been considering specific measures against cyberattacks since it pledged to bolster its cyberspace defense under its latest national defense guidelines launched last December.

Some defense experts say the ability to obstruct an enemy’s use of cyberspace could exceed the limits of the country’s exclusively defense-oriented policy.

The virus, to be developed by private companies, will be used only for defense purposes — not for pre-emptive attack — a ministry source said. Government policy allows cyberattacks only against a country or an organization considered equivalent to a country.