Hundreds of Hong Kong protesters demanded yesterday that the Chinese government exonerates the participants in pro-democracy demonstrations in Beijing's Tiananmen Square that it brutally suppressed 21 years ago.

The Chinese government still considers the 1989 protests a "counter-revolutionary riot", and public discussion of the student movement is taboo. But the military crackdown, which killed at least hundreds, is mourned openly every year in Hong Kong, a semi-autonomous Chinese territory that is promised Western-style civil liberties.

This year, however, Hong Kong democracy activists alleged that local police were trying to clamp down on their mourning activities.

On Saturday, police officers arrested 13 activists and confiscated a "Goddess of Democracy" statue dedicated to the Tiananmen victims and set up next to a shopping mall. Police said the activists did not have a licence to display the statue.

The activists pressed ahead with a scheduled protest yesterday, displaying a smaller version of the statue. Police did not interfere with this protest.

"Political persecution is shameful," the 400 protesters chanted in the rain before setting off for Hong Kong's government headquarters.

"No matter how harsh the crackdown, we will persist until the end with a firm hand," veteran activist Szeto Wah told the crowd.

"The Hong Kong government is so narrow-minded," protester Anthony Cheung said, adding he was worried that freedom of speech was being eroded in the former British colony.

"It is giving us less and less space to express our views," the 67-year-old pensioner said.

After most protesters dispersed, about 30 marched on to the Chinese government's liaison office in Hong Kong, where they scuffled with police guarding the building. They later staged a sit-in on the road in front of the compound, stopping traffic.

The activists plan to stage a candlelight vigil on Friday, the anniversary of the crackdown. The annual vigil usually draws tens of thousands of people.