Prosecutors searched the office of former METI chief Yuko Obuchi's support group and the home of a former aide Thursday as they launched a formal probe into political fund report irregularities linked to the one-time rising star of the Abe Cabinet.

The move by the Tokyo District Public Prosecutor's Office's special investigative arm prompted some of Obuchi's fellow lawmakers from all sides to call for her to resign from the House of Representatives. Obuchi, who belongs to the ruling Liberal Democratic Party, stepped down as chief of the prestigious Ministry of Economy, Trade and Industry last week after less than two months in office.

Prime Minister Shinzo Abe's administration has been hit by a spate of political funds scandals since he reshuffled the Cabinet in September. Abe said he would like to hear an explanation from Obuchi on the matter.