The Japan Aerospace Exploration Agency (JAXA) has experienced several cyberattacks since last year, the government said Friday.

The agency has begun an investigation to determine the scope of the damage caused by the attacks and taken measures to shut down the networks that may have been involved in the incidents, Chief Cabinet Secretary Yoshimasa Hayashi said.

“I would like them to proceed with the investigation and take the necessary measures,” Hayashi said, adding that the networks hit by the hackers did not host sensitive information pertaining to rockets or satellites.

A JAXA spokesperson declined to provide further details on the attacks, including the exact timings, due to the sensitive nature of the matter.

During the attacks, private data on JAXA employees as well as information on external parties — including companies and agencies cooperating with JAXA, such as the Defense Ministry, Toyota and NASA, among others — contained in over 10,000 files might have leaked, the Asahi Shimbun reported Friday.

Science minister Masahito Moriyama — who has direct responsibility over JAXA — denied that classified information had been leaked.

“There may be some concerns, but I don’t think the situation warrants serious ones,” he told a news conference.

For his part, Defense Minister Minoru Kihara has ruled out any impact on his ministry’s operations.

It’s not the first time that Japan’s space agency has experienced cyberattacks.

Last November, after several media reports brought the issue to light, the government confirmed that hackers had accessed JAXA servers in June 2023, but it said that they had not obtained any sensitive data.

According to the Asahi, a company entrusted with an internal investigation by JAXA found that a hacker group affiliated with China was involved in what are seen as targeted attacks on Japan’s space agency.

JAXA will disclose further information on the ongoing investigation at a later date, but the nature and timing of the announcement have yet to be decided, the spokesperson said.

Despite a recent increase in military spending and an increasingly assertive posture on the security front, Japan’s cyberdefense capabilities have lagged behind those of its international partners.

Cyberattacks against critical infrastructures, as well as private citizens, have been on the rise lately.

Last summer, a ransomware attack that hit the Port of Nagoya caused significant delays to operations.

Amid these attacks, the government is considering submitting legislation as early as possible to bolster the country’s ability to react to cyberattacks against critical infrastructure and improve cooperation between the public and private sectors.

A panel of experts on the issue held its first meeting earlier this month.