A lawmaker from the largest faction within Japan's ruling Liberal Democratic Party was arrested Sunday over allegations linked to a political fundraising scandal that has engulfed the party.

Prosecutors suspect Yoshitaka Ikeda, a member of the House of Representatives, received a total of 48.26 million yen ($333,000) over five years through 2022 from slush funds created by the faction formerly led by late Prime Minister Shinzo Abe.

House of Representatives member Yoshitaka Ikeda. (Kyodo)

His policy secretary, Kazuhiro Kakinuma, 45, was also arrested. The two are accused of failing to declare the money Ikeda received in political fundraising reports.

In responding to the arrest of Ikeda, Prime Minister Fumio Kishida expressed deep concern, saying he took the incident very seriously.

"We as a party should have a strong sense of crisis and restore public trust in politics," Kishida told reporters.

LDP Secretary General Toshimitsu Motegi said the party decided to expel Ikeda from its membership.

Prosecutors decided to arrest the 57-year-old Ikeda to mitigate the risk of him potentially concealing or destroying evidence.

The prosecutors have determined that the fourth-term lawmaker colluded with Kakinuma, who was in charge of creating a report on income and expenditure.

The intraparty group allegedly failed to declare hundreds of millions of yen in fundraising party revenue in political funding reports that were transferred to its members, sources close to the matter said.

The amount is believed to have totaled about 500 million yen over a five-year period through 2022, for which the statute of limitations has not expired under the political funds control law, the sources said.

The law requires an accountant to submit a report on income and expenditure, and failure to report can result in imprisonment for up to five years or a fine of up to 1 million yen.

Lawmakers can be accused of committing a crime when they are thought to have colluded with an accountant in charge. Kakinuma is responsible for Ikeda's reporting.

Several Abe faction lawmakers are alleged to have pocketed a portion of the revenue they collected through the sale of party tickets above their quotas, with the total sum reaching at least 80 million yen over the period, the sources said.

In the Abe faction, called Seiwaken, or the Seiwa policy study group, the majority of its 99 members are suspected of having received funds, but Ikeda allegedly took significantly more than others, the sources added.

Japanese Prime Minister Fumio Kishida speaks to reporters at the premier's office in Tokyo on Jan. 7, 2024. (Kyodo)

Following the arrest of Ikeda, the faction has issued an apology and said it will cooperate with the investigation.

The prosecutors searched the offices of the Abe faction and Ikeda to collect documents and other materials related to the allegations.

The prosecutors are investigating the involvement of senior lawmakers, including some who served as the faction's secretary general, as they are believed to have known the flow of money within the group.

Former LDP Diet affairs chief Tsuyoshi Takagi is currently the faction's secretary general, while former Chief Cabinet Secretary Hirokazu Matsuno and former trade minister Yasutoshi Nishimura previously held the position.

All have been questioned voluntarily.

The prosecutors are also investigating another faction headed by former LDP Secretary General Toshihiro Nikai, who has agreed to answer questions voluntarily over similar funds allegations, the sources said.

The slush fund scandal emerged following a criminal complaint alleging five LDP factions, including the fourth-largest one that Kishida headed until early December, underreported revenue from political fundraising parties.

LDP factions have traditionally set quotas for lawmakers on the sale of party tickets, usually priced at 20,000 yen. In some groups, if lawmakers surpass their targets, the extra funds are passed back to them as a type of commission.

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