Filed at 7:44 a.m. ET

TAIPEI, Taiwan (AP) -- Tens of thousands of red-clad protesters thronged Taiwan's capital Saturday, demanding that President Chen Shui-bian resign over a series of alleged corruption scandals involving his family and inner circle.

The color of their clothes symbolizing anger, the protesters shouted slogans and gave the ''thumbs down'' gesture, emblematic of their feeling that Chen should resign to restore the dignity of the self-governing island of 23 million people.

Police estimated 90,000 people jammed a broad boulevard adjacent to the ornate Presidential Office Building in Taipei, though protest organizers claimed they reached their target of 200,000.

Protest leader Shih Ming-teh said Taiwan would be paralyzed of Chen served out his term, which ends in May 2008.

''The people of Taiwan have the power to ask Chen to step down,'' Shih said. ''We will not stop this protest until he does.''

As rain began to fall, Shih sat down on the boulevard to symbolize his steadfastness, and the crowd followed suit. He has vowed to stage a sit-in protest outside the Presidential Office Building until Chen steps down.

Chen has been under fire for more than four months over allegations that his relatives and aides have exploited their connections to him for illegal financial gain.

On Thursday, the Presidential Office acknowledged that prosecutors questioned Chen last month about the use of false invoices to account for part of a secret fund used for Taiwanese diplomatic activities. Chen admitted his office had used false invoices in the accounting of the diplomatic fund. However, the office said the ruse was necessary because of the fund's highly secretive nature.

In July, his son-in-law was indicted for alleged insider trading involving a local development firm, a charge he denies. First lady Wu Shu-chen is also under investigation for allegedly profiting from the transfer of an upscale department store to new owners. Chen's office insists she was not involved.

Many protesters appeared to be supporters of the opposition Nationalist Party, though there were also some disappointed followers of Chen's Democratic Progressive Party.

''I want him to go,'' said Ted Lai, 45, a Taipei salesman who supported Chen in the past. ''He has been corrupt and he has done many things wrong.''

Barbed-wire barricades kept the protesters away from the presidential offices. Police said Friday they had contingency plans to deploy 2,000 officers and 600 barricades if violence broke out.

Last month, Shih announced he would enlist 1 million Taiwanese to donate $3 each to support his campaign to get Chen to step down. He said he reached his goal in a week.

In a letter published in leading Taiwanese newspapers Saturday, opposition leader Ma Ying-jeou -- a strong favorite to lead the National Party in 2008 presidential elections -- said Chen's party should not become ''an accomplice to corruption.''

''We will not be happy to see the DPP collapse because of its support for Chen,'' Ma said, calling on the party to introduce a recall motion against Chen in the legislature.

In June, the Nationalists and their allied People First Party failed to push through a bill calling for a national referendum on whether to recall the president. The bill failed to receive the required two-thirds backing from lawmakers.

On Friday, about 5,000 of Chen's backers rallied in Taipei in support of the embattled president.

Chen spent Saturday visiting his hometown of Kuantien in southern Taiwan, where his supporters burned red shirts to express their disapproval of Shih's campaign.