TOKYO - Japan's ruling Liberal Democratic Party led by Prime Minister Fumio Kishida lost all three lower house seats on Sunday, as the country's main opposition party won big by sweeping victories in three key by-elections.

The Constitutional Democratic Party of Japan emerged victorious in three crucial by-elections, including a closely watched race in Shimane Prefecture, traditionally considered a conservative stronghold, long dominated by the LDP.

Members of Kishida's party had warned before Sunday's by-elections that voter anger could result in a change of government after the next general election, which must be held before Oct 30, 2025, but could be called much earlier, the Japan Times reported on Sunday

The by-elections, the first elections since the LDP's slush fund scandal surfaced late last year, were held in Shimane and Nagasaki prefectures, as well as one in Tokyo. The seats were previously held by the conservative LDP before they became vacant.

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Local analysts pointed out that the public's dissatisfaction with the ongoing scandal within the LDP was much underscored by the CDP's wins in the Shimane No. 1 district, the Nagasaki No. 3 district and the Tokyo No. 15 district, while recent polls showed record-low support rates for the prime minister.

"We faced political headwinds throughout the election campaign," LDP Secretary-General Toshimitsu Motegi told the press, citing fierce backlash from the public.

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Members of Kishida's party had warned before Sunday's by-elections that voter anger could result in a change of government after the next general election, which must be held before Oct 30, 2025, but could be called much earlier, the Japan Times reported on Sunday.

Sunday's results now mean Kishida could face stronger interparty resistance if he seeks re-election as LDP president, with his term due to finish this September, the paper added.

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At the end of last year, in the wake of the unfolding scandal where five major factions were suspected of paying kickbacks to member lawmakers who sold fundraising party tickets above their quota without recording the amount as revenue in its political fund reports, over 10 senior officials or heavyweight lawmakers have stepped down from their positions in Kishida's cabinet or in the LDP.