Tokyo (AFP) - Japan's hawkish defence minister resigned Friday over a long-brewing scandal involving the handling of military documents, in a major political blow to Prime Minister Shinzo Abe.
Abe, who has seen his popularity plummet in recent weeks over several controversies, apologised for the saga.
"I apologise from the bottom of my heart to the people for this situation in which a minister resigns," Abe told reporters after Tomomi Inada quit.
Abe added he "must seriously accept the people's severe criticism".
Inada's nearly year-long stint was characterised by controversy, but she resigned over criticism of her ministry's handling of log reports filed by Japanese peacekeepers in South Sudan showing worsening security.
Inada told a press conference where she announced her resignation: "I feel a keen responsibility."
The prime minister this week dodged opposition questioning in parliament over claims of favouritism in a business deal, an accusation he has vigorously denied.
His government's public support ratings have fallen precipitously over the summer, with voters punishing the LDP in local Tokyo elections early this month.
The party suffered a drubbing in the vote for Tokyo's municipal assembly that media and analysts chalked up to a growing perception of "arrogance" on the part of his government.
It lost more than half its seats, with the result seen as a bellwether for national political sentiment.
The chief of staff of Japan's Ground Self-Defence Force, the army, also resigned, as did the top ranking civil servant in the defence ministry.
The shakeup in the top echelon of Japan's defence establishment comes as the country remains on alert over possible further North Korean missile launches.
Abe said that Fumio Kishida, the foreign minister, will also serve as interim defence chief until a replacement for Tomomi Inada is named.
"We have not a moment to lose in security issues," the prime minister said.
Abe, who became prime minister for a second time in December 2012 with a vow to rejuvenate Japan's economy, will reportedly revamp his cabinet next week in a bid to reboot the government, but he faces an uphill climb.
- 'Heavy blow to Abe' -
"Inada's resignation has dealt a heavy blow to Abe," said Shinichi Nishikawa, professor of political science at Meiji University.
"Three months ago, Abe was expected to stay in power until 2021 but the situation has changed greatly," Nishikawa told AFP. "He used to face no rivals within the LDP but his position now appears shaken."
Inada, a close confidante of Abe who shares his staunchly nationalist views, was appointed defence minister in August 2016, a time when she was touted as a possible future leader.
During her tenure, Inada delighted conservatives but drew domestic and international criticism in December when she prayed at a controversial war shrine in Tokyo -- the day after accompanying Abe on a symbolic visit of reconciliation to Pearl Harbor in the United States.
Yasukuni Shrine honours millions of mostly Japanese war dead, but is contentious for lionising senior military and political figures convicted of war crimes by an international tribunal.