Many protesters wore masks to guard against Sars

Organisers say 50,000 people attended the annual commemoration, though other estimates say there were about half that number.

As well as honouring the hundreds or possibly thousands of people killed when tanks were ordered into the square to quash protests in 1989, this year's vigil also highlighted fears of new subversion laws.

Protests have continued to be tolerated in Hong Kong since its return to Chinese sovereignty in 1997, but activists say proposed security legislation will cut back civil liberties in the territory.

Rally 'important'

Correspondents say Victoria Park in the city centre became a sea of candlelight as protesters sang songs and made speeches to commemorate those who died, most of whom were students.

Many people wore face masks as protection against the Severe Acute Respiratory Syndrome (Sars) which continues to afflict Hong Kong.

Activist Leung Kwok-hung said the vigil remained important as "Hong Kong is the only city [under Chinese sovereignty] where we can still hold a massive demonstration each year to mark 4 June".

Thousands held up candles to remember the dead

Lee Cheuk-yan, spokesman for protest organisers Hong Kong Alliance in Support of Patriotic Democratic Movement in China, said fears over Article 23 of Hong Kong's Basic Law, which will outlaw treason, sedition and subversion, were generating worry.

"People still remember 1989 and will continue to commemorate those who died on 4 June... even when Article 23 laws are in place," he vowed.

'Protect freedoms'

One of the crowd, teacher Albert Tsui Ga-wai, said he was taking the opportunity to show his opposition to the new laws.

"What separates us from China is freedom and human rights. These new laws will mean Hong Kong more strongly resembles China," he was quoted as saying by the AFP news agency.

"I fear freedoms here will erode till we are barely distinguishable and we need to stop that now."

Tiananmen Square itself was largely empty throughout the day

Activist Law Yuk-kai of the Hong Kong Human Rights Monitor predicted the law will discourage dissent and will eventually be used to silence critics.

"The problem is, the water's being heated up only gradually," he said. "At one point, the frog will notice it's cooked."

In China itself, correspondents say Tiananmen Square was largely deserted.