Taiwan leader Chen Shui-bian's chief of staff on Sunday rejected opposition calls for Chen's ouster over an insider trading scandal embroiling Chen's son-in-law, saying he has done no wrong. 

The "president" has not done anything wrong, Mark Chen told reporters. The two men are not related.

Thousands of people rallied in Taipei on Saturday, joining an opposition call to demand Chen Shui-bian's resignation.

Shouting "Ah-bian step down", they gathered near the "presidential office" in central Taipei as riot police with baton and shields kept watch behind barbed-wire barricades set up to keep protesters at bay.

Chen, whose nick-name is Ah bian, has faced growing pressure to step down after his son-in-law was detained last month on suspicion of using insider information to buy shares of Taiwan Development Corp. from a bank.

"Probe graft to the very end", said placards carried by the demonstrators.

Chen, whose approval rating has sunk to new lows, and his son-in-law, Chao Chien-ming, have apologised. And Chao, who has been detained, has denied any wrongdoing.

Earlier this week, Chen has agreed to yield some powers to "Premier" Su Tseng-chang and approved the resignations of his closest aides in an apparent attempt to deflect pressure from both supporters and opponents to step down.

But Chen's moves were too late for the People First Party, Taiwan's second-biggest opposition party, which organised the protest.

Analysts said the struggling party was seeking to seize the initiative after Ma Ying-jeou, chairman of the main opposition Nationalist Party, angered supporters by opposing calls for Chen to be recalled.

NO-CONFIDENCE VOTE

Ma called on Saturday for a no-confidence vote in the parliament against the "cabinet" because the opposition lacks the two-thirds parliamentary majority for a recall motion to pass.

Under Taiwan's "constitution," a no-confidence vote against the cabinet, if passed, would force Chen to either choose a new "premier" or dissolve parliament and call snap elections.

The Nationalists have a razor-thin parliamentary majority and have eyed the "premiership" since Chen won the 2000 elections ending more than five decades of one-party rule. Chen won re-election in 2004.

Ma urged all the people who are unhappy with the Democratic Progressive Party's corruption to stand forward and loudly tell the Taiwan leader, "please, resign and step down!" 

Yu Shyi-kun, chairman of the ruling Democratic Progressive Party, said the protest exposed the growing divisions in the opposition camp.

Even former "president" Lee Teng-hui, a political ally of Chen, has suggested the Chen should consider stepping down.

"The leader must be changed if he commits a mistake. 'The son of Taiwan' is not just one person," Lee said referring to Chen's self-professed nickname. "Sons of Taiwan are everywhere. Everyone here are sons of Taiwan," he added.