By Caroline Gluck
BBC News, Taipei
The crowds of protesters gave the president the thumbs down
Hundreds of thousands of demonstrators have been surrounding the presidential office in Taiwan, calling on President Chen Shui-bian to step down.
The mass action took place as the president took part in a ceremony marking Taiwan's National Day.
The crowds wore red T-shirts to symbolise public anger over corruption scandals surrounding the president's aides and family.
About 5,000 police were on duty but the protests were largely peaceful.
Huge crowds gathered at four main points around the presidential office and called out their demands for the president's resignation.
The crowds gave a thumbs down sign, showing their disapproval of his leadership.
Barbed wire barricades kept the crowds several streets away from the area where government officials were gathered.
Chaos and turmoil
In his speech, President Chen said he had always stood firm against corruption and that no-one was above the law, including himself and his family.
He admitted that since taking office six years ago, ending five decades of rule by the Nationalist party, Taiwan had faced political chaos and turmoil.
He said Taiwan's predicament was similar to the growing pains of other emerging democracies and he said partisan differences should not be allowed to undermine the island's democracy, peace and prosperity.
But as he spoke, opposition legislators and critics in the presidential square began chanting calls for him to step down and some small scuffles broke out.
It was clearly an embarrassing moment for President Chen, who was addressing foreign delegates and government officials.
But he has continually denied any wrongdoing and has said he will serve out his full term in office.