Defense Minister Tomomi Inada resigned Friday to take responsibility for a suspected coverup involving the daily activity logs of Japanese troops serving as U.N. peacekeepers in South Sudan.
"I accepted (Inada's) resignation out of respect for her desire to take responsibility for having caused disruption," Prime Minister Shinzo Abe told reporters at his office, admitting his responsibility for appointing her and apologizing to the public.
The decision by Inada, who is known for sharing Abe's conservative views, comes just before a Cabinet reshuffle planned for next week in which the prime minister was already widely expected to replace her.
Foreign Minister Fumio Kishida will take over Inada's duties alongside his own until a new defense chief is appointed, Abe said.
"We cannot allow there to be any gaps in our national security," Abe said.
Shortly beforehand, Inada announced she had tendered her resignation to coincide with the defense ministry's release of the results of its internal probe into the handling of the logs.
"This issue has given (the public) an impression that could damage their trust in the governance of the Defense Ministry and SDF," she told a press conference.
"As the defense minister who directs and supervises the Defense Ministry and SDF, I am acutely aware of my responsibility...and I have decided to leave the role," Inada said.
The probe did not conclusively find that Inada had a hand in concealing the logs, but concluded other ministry and defense force officials had violated the law relating to information disclosure.
Inada, a fourth-term lower house member, is the sixth minister to resign since the start of Abe's second stint as prime minister in December 2012.
In April, then disaster reconstruction minister Masahiro Imamura stepped down for saying it was "a good thing" the March 2011 earthquake and tsunami struck northeastern Japan rather than the much more-populous Tokyo area.
Abe is considering picking someone with prior experience of the defense portfolio, such as Itsunori Onodera, to succeed Inada next week in a bid to regain public trust in the Defense Ministry and the SDF, according to sources close to the government and ruling coalition.
The peacekeepers' logs recorded the deteriorating security situation in the fledgling African country and their disclosure last year could have adversely impacted the government's push to continue the troops' participation in the U.N. mission and assign them new, possibly riskier, security responsibilities.
The controversy regarding the logs dates back to December, when the ministry turned down an information disclosure request for logs covering the Ground Self-Defense Force activities in South Sudan in July last year, saying the logs had been deleted.
The ministry then reversed its previous explanation, saying some of the data had been found on a computer in the SDF Joint Staff Office and releasing sections of it.
But top SDF officials reportedly already knew then that the GSDF actually had the data. Government sources claim Inada approved a coverup.
In the results of the probe released Friday, inspectors said they "cannot rule out the possibility" that Inada heard "some remarks" about the existence of the digital data logs in the GSDF's possession during meetings with senior defense bureaucrats and Ground Staff Office members in mid-February.
But they were unable to conclude that Inada was notified in writing about the existence of the data or was asked to endorse a decision not to let the public know that the data had not in fact been discarded.
The 58-year-old lawyer-turned-politician assumed the defense portfolio in the previous Cabinet reshuffle in August last year.