Japan's Defense Ministry on Monday dismissed a Maritime Self-Defense Force captain over the alleged leak of state secrets to someone without security clearance, making it the first case of the secrecy law being enforced since it came into effect in 2014.

A Self-Defense Force criminal investigation unit referred the captain, Takashi Inoue, 54, to prosecutors for allegedly giving classified information to a former MSDF admiral who had already retired from the force, according to the ministry.

In March 2020, Inoue disclosed secret information regarding "situations surrounding Japan" as well as the MSDF's troop operations and training, the ministry said.

He has admitted the allegation is true, but there has been no evidence of the information being passed on to others through the former admiral, government sources said.

Information related to the performance of MSDF defense equipment or the capabilities of Japanese troops were not among the leaked secrets, ministry officials told reporters, but they declined to say whether intelligence gathered by U.S. forces was included.

Adm. Ryo Sakai, chief of staff of the MSDF, apologized for the incident at a press conference, saying it could "undermine the public's and other nations' confidence in the MSDF," and vowed to take preventive measures.

Maritime Self-Defense Force Chief of Staff Adm. Ryo Sakai bows in apology during a press conference at the Defense Ministry on Dec. 26, 2022. (Kyodo)

The ministry said the former admiral requested an MSDF unit in charge of collecting and analyzing information in January 2020 to brief him about the latest state of security affairs but had not demanded that classified information be disclosed.

As for a reason behind the request, the former admiral explained that he would often give public speeches so he needed to be informed about the latest situations, according to the officials.

The former admiral told Kyodo News he never asked for state secrets and "did not know which part was state secrets."

The investigative unit was notified of the breach by a whistle-blower, government sources said.

The sources also said the SDF investigative body will probe Former MSDF Chief of Staff Hiroshi Yamamura in connection with the information leak by Inoue, one of his subordinates at the time.

Yamamura headed the MSDF from April 2019 until March this year, when he retired as an MSDF officer.

Under the secrecy law, civil servants and others who disclose sensitive information designated as state secrets, such as those regarding foreign policy, defense, counterterrorism and counterespionage, can face up to 10 years in prison.

The law requires security clearance for anyone handling information considered to be state secrets.

There were a total of 693 state secret cases as of the end of June, of which 392 were designated by the Defense Ministry, according to the Cabinet Secretariat.

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