BEIJING (AFP) - China on Wednesday imposed smothering security in central Beijing on the 25th anniversary of the Tiananmen Square crackdown, a bloody watershed in history that remains taboo in the communist nation.
Counting down to the anniversary, the United States demanded the release of scores of people detained in the run-up, as the semi-autonomous city of Hong Kong prepared for an annual candlelit vigil that this year is expected to draw as many as 200,000 attendees.
Thousands of police and security forces, some armed with automatic rifles, have been deployed across the Chinese capital.
Police trucks were numerous on and around Tiananmen Square on Wednesday with fire engines and ambulances also visible.
Some security officers had fire extinguishers placed ready nearby. Security has also been heightened recently after a spate of attacks that authorities blame on separatists from the far-western region of Xinjiang.
Tourists and vendors went about the vast public square at the heart of Beijing, but uniformed and plainclothes officers were stationed at every corner and checking the ID cards of passers-by.
One Australian woman said she was prevented from visiting the Forbidden City, where China's emperors lived, as she was not carrying her passport - not normally a requirement for tourists entering the historic site.
An AFP journalist was ordered to delete photos of scuffles between police and frustrated pedestrians waiting to enter the main part of the square on Wednesday morning.
An unidentified man followed and harassed an AFP journalist for several blocks after passing by the square on bicycle on Tuesday night.
Hundreds of unarmed civilians - by some estimates, more than 1,000 - were killed during the June 3-4 crackdown of 1989, when soldiers crushed months of peaceful protests by students who were demanding political reform to match China's nascent economic opening up.
Since then, China has worked hard to quash public memories of the crackdown, censoring any mention of the incident from online social networks and detaining scores of activists, lawyers, artists and others in recent weeks.
On the eve of the anniversary, Washington renewed its call for Beijing to allow greater political freedoms and urged the release of those arrested.
"We've very clearly called on the Chinese authorities to release all the activists, journalists and lawyers who have been detained ahead of the 25th anniversary," State Department spokesman Marie Harf told reporters.
"I think it's time to allow some more space, quite frankly, for discussion in their own country, particularly around this kind of anniversary," she added.
Foreign news organisations in Beijing have been warned by police and the Chinese foreign ministry against doing any news-gathering related to the anniversary, or else risk facing "serious consequences", including the possible revocation of their visas.
In one incident reported on Monday by the Foreign Correspondents' Club of China, a French television crew was detained for six hours by police as they attempted to interview passers-by on a downtown Beijing street.
The crew was trying to show people the iconic "Tank Man" photo from the crackdown, when a lone individual marched out in front of a line of tanks, halting their progress.
In 1989, the demonstrations and subsequent crackdown played out on television screens across the world, and Beijing was briefly made a pariah in the West.
But 25 years later, the ruling Communist Party's authority is intact and its global clout continues to rise in line with the country's rapid growth, which has taken China to second place in the global economic rankings behind only the United States.
China's state-run media on Wednesday made brief mentions of the anniversary in their English-language editions.
The nationalistic Global Times contended in an editorial that China "has shielded relevant information in a bid to wield a positive influence on the smooth development of reform and opening up".
"Chinese society has never forgotten the incident 25 years ago but not talking about it indicates the attitude of society," it added.
The paper's Chinese-language edition did not directly mention the crackdown.
But under the headline "Anti-China forces in the West making every possible effort to harm China", the paper vaguely alluded to the crackdown by accusing the West of "actively provoking trouble for China recently and being very emotional".