Japanese Prime Minister Kishida Fumio is facing increasing pressure over a scandal involving his main ruling Liberal Democratic Party. Two LDP factions are suspected of not reporting some revenue collected from ticket sales for fundraising events. Tokyo prosecutors searched their offices Tuesday.

The Abe and Nikai factions are suspected of paying kickbacks to offices of member lawmakers who sold tickets in excess of their quota. It has suspected the factions did not record those amounts as revenue in their political fund reports -- a possible violation of political funds control law.

Offices of Abe faction lawmakers are estimated to have received unrecorded funds worth about 3.5 million dollars over five years.

The former secretary of a lawmaker in the group tells NHK the faction explicitly told him not to include the kickback in the lawmaker's political fund report.

He said, "I asked if the money was a slush fund, and whether it was really OK not to declare it. I was told we would get in trouble if we did report it, so I shouldn't do so."

A reporter asked the secretary general of the Abe faction if he instructed anyone not to declare part of the revenue, but he wouldn't answer.

Takagi Tsuyoshi said, "The matter is currently under investigation. I'm very sorry."

Nikai Toshihiro heads the Nikai faction. He says he will cooperate with the investigative authorities.

The leader of the LDP's junior coalition partner is calling for drastic reform.

Yamaguchi Natsuo of Komeito said, "The LDP should come up with a plan to convince the public that its members are resolved to rectify themselves. It should show how they will carry out reform to start anew."

Opposition party leaders are urging the LDP to properly respond to the situation quickly.

Constitutional Democratic Party President Izumi Kenta said, "It's an abnormal situation. More than one policy group of the LDP has been searched. That itself is unprecedented. The prime minister should announce as soon as possible whether his Cabinet can truly live up to the public mandate."

Democratic Party for the People President Tamaki Yuichiro said, "The LDP is the one that knows the most about this affair, so I think it should swiftly hold itself accountable. There is no need to wait for the investigation to end."

Kishida says he takes the public's distrust over the matter seriously.

He said, "Members of our party must do all we can to win back public trust with a strong sense of urgency."

Kishida replaced four cabinet ministers belonging to the Abe faction last week. He says he wants two ministers belonging to the Nikai faction to remain in cabinet.