Japanese Prime Minister Taro Aso's ruling party appeared to be heading for defeat on Sunday in a Tokyo election seen as a crucial test of his popularity ahead of a nationwide vote, media reports said.
A drubbing in the Tokyo polls could increase internal party pressure on Aso to quit before general elections he must call by September, with the opposition seeking to end the ruling party's half-century of almost unbroken rule.
The opposition Democratic Party of Japan (DPJ) looked set to win the most seats in Sunday's vote for the Tokyo metropolitan assembly, public broadcaster NHK and Kyodo News reported, based on their own projections.
Aso's Liberal Democratic Party acknowledged the apparent bloody nose from voters in the sprawling capital.
"We have to sincerely face the severe judgement from Tokyo residents," said senior LDP official Nobuteru Ishihara.
Opposition leader Yukio Hatoyama said his party, which controls the upper house, would submit a motion of no-confidence against Aso in parliament "as soon as possible".
"We will urge (Aso) to ask for the people's voice by dissolving the lower house and calling a general election," he said.
Based on early official results and its own projections, NHK estimated that the DPJ had won at least 50 assembly seats out of a total of 127, against 38 shared between Aso's LDP and its coalition partner New Komeito.