Beijing in lockdown for 25th anniversary of Tiananmen crackdown

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 Wednesday with fire engines and ambulances also visible.        

In this combination of photos, a file photo taken
June 5, 1989, top, shows a lone Chinese man
standing to block a line of tanks heading east on
Beijing's Changan Blvd. near Tiananmen Square,
and in a May 27, 2014 photo of the same spot,
bottom, almost 25 years later. AP Photo

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...