The first-ever open demonstration in China against the army's intervention in Tiananmen Square in Beijing nine years ago is due to take place in Hong Kong later today.

Organisers have predicted a large turnout to commemorate the hundreds, perhaps thousands, of pro-democracy demonstrators who were killed in 1989.

But they expect fewer people to participate than the fifty-five thousand people who marked the anniversary last year just three weeks before Britain returned Hong Kong to Chinese rule.

The BBC Hong Kong correspondent says one recent opinion poll suggests that public outrage about the killings is mellowing.

Opposition groups say police in the rest of China have warned dissidents not to stage protests before President Clinton's visit to China this month.