Security was tight on Beijing's central Tiananmen Square on Tuesday ahead of the 19th anniversary of the 1989 crackdown on pro-democracy protests that left hundreds, possibly thousands, dead.
Police vans were circling on and around the square, the focus of major bloodshed nearly a generation ago, as tourists were arriving in numbers on a grey, rainy day.
The Tiananmen Massacre is a taboo subject in China and the country's state-controlled media was silent on the sensitive anniversary taking place just 66 days ahead of the Beijing Olympics.
China's communist party has never offered a full account of the crackdown on the night of June 3-4, when troops and tanks gunned down students and other protestors who had been demonstrating peacefully in the central square for weeks.
The government branded the pro-democracy protests a counter-revolutionary rebellion and hunted down ringleaders and jailed hundreds of suspects.
This week New York-based Human Rights Watch urged China to release dozens of people who it said were believed to be still held in prison on charges related to the 1989 protests.
"The Chinese government should honour its commitment to improve human rights before the 2008 Beijing Olympics by releasing the estimated 130 Tiananmen prisoners improperly arrested or tried," the rights group said in a statement.
China is using the Olympics as its "coming out party," the statement said, and Tiananmen Square is being used as a venue for official events such as the start of the marathon road races.
The square was used in March to launch the Beijing Olympic torch relay in a lavish event attended by President Hu Jintao.
"Beijing's use of Tiananmen Square as a macabre prop for China's Olympic coming-out-party' adds insult to injury," said Sophie Richardson, Asia advocacy director at Human Rights Watch.
"The Chinese government should show the global Olympic audience it's serious about human rights by releasing the Tiananmen detainees."
In the lead-up to the August 8-24 Olympics, China has stepped up security around the square where plain-clothes police and video cameras closely monitor visitors.
Police have been authorised to make random searches of visitors to the square to reduce security threats ahead of the Games, state press reported recently.