Japan's Prime Minister Sousuke Uno, stung by allegations he hired geishas for sex, suffered a major political setback Monday in local Tokyo elections, adding to expectations he will be forced to resign.

Uno, 66, touted as "Mr. Clean" when he took office a month ago, promised to rid Japan of its system of political bribery that had reached epidemic proportions and eventually forced the resignation of Prime Minister Noboru Takeshita.But before Uno could launch his political reform, he found himself battling reports he paid several geishas for long-term sexual relationships.

Sunday, Tokyo's 9 million voters abandoned Uno's ruling Liberal Democratic Party in elections for the Tokyo Metropolitan Assembly.

Uno's party lost one-third of the 63 seats it formerly held while the Japan Socialist Party, which has called for Uno's resignation, tripled its seat count to 36, including seven independent candidates it endorsed.

The 128-member Tokyo assembly will be made up of 44 Liberal Democrats, 36 Socialists and 48 independents or members of minor parties.

The results, coming just three weeks before a national parliament election, have increased pressure on Uno to resign and could force the Liberal Democratic Party to reconsider its policies.

"Uno's government will not continue for long," said Tadashi Ariga, professor of politics at Hitotsubashi University. "I think he will be replaced by autumn."

Most political analysts, including some within Uno's own party, expect he will resign following the election for the upper house of the Diet, Japan's parliament, on July 23.

Uno, who is said to be in a state of depression over the sex scandal and his rapid fall in popularity, reportedly offered to resign last week but was persuaded to stay on by party leaders.

During the 10-day Tokyo election campaign, Uno was shunned by candidates of his own party, some of whom made an unprecedented call for the prime minister to stay away from their districts because of the publicity over the sex scandal.

When asked by reporters if his alleged extramarital affairs hurt his party in the Tokyo elections, Uno said in English, "No comment."

Uno has made it his policy not to discuss the sex allegations despite new charges that have surfaced each week since he took office.

The damage to Uno may eventually be overshadowed by the threat the Tokyo elections portend for the Liberal Democratic Party.

The Liberal Democrats have been in power in the Diet since 1955, guiding Japan with a conservative, pro-business hand that has helped the country become the world's second-largest economic power.

But the Liberal Democrats' popularity has sunk to a historic low because of the Uno sex scandal, the influence-buying scandal that forced Takeshita's resignation and an unpopular 3 percent sales tax enacted in April.

The scandals have painted a picture of a ruling party grown arrogant and wealthy from its three-decade lock on power.

"This situation is the result of a long period of dominance by a single party," said Japan Socialist Party Chairwoman Takako Doi. "This should no longer be allowed to continue.

"The Socialist Party is more in touch with the people's daily lives," she said.

The strong showing by the Socialist Party in the Tokyo election signals the possibility Socialists could make significant gains in the Diet election in July.

The Socialist Party favors an unarmed, neutral foreign policy and has until recently opposed Japan's military cooperation with the United States.

"This is the beginning of the end of one party - Liberal Democratic Party - politics in Japan and the start of a truly multi-party system," said Kuniko Inoguchi, a political commentator.

Women, an unlikely source of political power in Japan, played a key role in the Tokyo poll, voting in larger numbers than men.

About 61 percent of women eligible to vote did so, compared with 56 percent of men voters, reversing the usual voting pattern.

Seventeen of the 33 female candidates running were elected.

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(Additional information)

Baker begins trip

Secretary of State James A. Baker III left for Japan Monday for talks with officials from other nations on a proposed $2 billion-a-year aid and investment package for the Philippines. The five-year aid program is designed to help the Philippines' young democracy overcome economic backwardness and a determined leftist guerrilla movement.