June 4 (Bloomberg) -- China opened Tiananmen Square to the public this morning after ringing the area with metal fences overnight to stop people from commemorating the 20th anniversary of the army’s 1989 crackdown on pro-democracy demonstrators.

Uniformed and plainclothes police patrolled the square, the world’s largest public piazza, assisted by security guards and cadres from local neighborhood-watch committees. Men with cropped hair were stationed every few paces, some wearing red lapel pins of the national flag. Visitors were forced to pass bags and cameras through X-ray machines.

The U.S. State Department urged China yesterday to openly examine the “darker events” of its past and engage in dialogue with the families of victims. Taiwan President Ma Ying-jeou said today the bloody incident was a painful chapter in history that must be faced.

“China can honor the memory of that day by moving to give the rule of law, protection of internationally recognized human rights and democratic development the same priority that it has given to economic reform,” State Department spokesman P.J. Crowley said at a briefing in Washington yesterday.

Student demonstrators calling for government reform and an end to corruption occupied Tiananmen Square in the heart of the Chinese capital for five weeks in the spring of 1989. Between the evening of June 3 and the early hours of June 4 of that year, soldiers backed by tanks opened fire on civilians in and around the square.

Casualty Estimates

Estimates of the number of deaths vary. Beijing’s mayor said in a 1989 report to the government that about 200 civilians died, while the U.S. Embassy in the city estimated that the death toll exceeded 1,000. Tiananmen Mothers, a Beijing-based group of family members of victims, has verified 195 deaths.

China’s government wants to express its “strong dissatisfaction” with yesterday’s State Department comments, foreign ministry spokesman Qin Gang said today in Beijing.

The government has defended its handling of what it calls the “incident,” by pointing to the country’s economic development since 1989. The economy had expanded 17-fold through 2008 to become the world’s third largest.

“China’s Communist Party and the government have already drawn a clear conclusion” on the events of June 1989, Qin said today, echoing a comment last week by spokesman Ma Zhaoxu. “China’s economic and social development over the past 30 years have yielded great achievements.”

Forbidden City

Tiananmen, or the Gate of Heavenly Peace, is the southern entrance to the Forbidden City, the former imperial palace built in the 15th century. A portrait of Mao Zedong faces the square from the southern wall of Tiananmen, where he proclaimed the establishment of the People’s Republic of China in 1949.

Security in the square will probably be stepped up again on Oct. 1, when the Chinese military is set to hold a parade to mark the 60th anniversary of Communist Party rule. Today, at 10 a.m. Beijing time, about 1,500 people were in the square.

A dozen women wearing t-shirts of the 2008 Beijing Olympics volunteers sat around on plastic stools, bottles of mineral water at their feet. A man in a blue t-shirt, who declined to give his name, said he’s one of 30 apartment security guards assigned to the square, earning 30 yuan ($4.40) for his 6 a.m. to 4 p.m. shift.

Restricting Web Sites

The Chinese government has also restricted access to overseas Web sites including Twitter Inc.’s social-networking service and Microsoft Corp.’s Bing.com search engine.

“This was the first time so many big sites all went down all at once,” said Jeremy Goldkorn, founder of Danwei.org, a China-based blog focused on the media and Internet industries. “The government doesn’t want any messing around.”

Chinese Internet users have employed code words to circumvent government monitoring. Messages circulated on San Francisco-based Twitter in recent weeks asking Internet users in China to turn their Web logs gray to commemorate the crackdown, referring to it as “May 35th,” “535” or “VIIV” -- Roman numerals signifying June 4.

The clampdown extended to television broadcasts as CNN went blank in Beijing and Shanghai during segments on the crushing of the 1989 protests. Censors cut out articles on the anniversary from foreign newspapers, including the Hong Kong-based South China Morning Post and the Financial Times, before they were delivered in China.

Surveillance of Critics

Authorities have also tightened surveillance over government critics in the run-up to June 4 while two leaders of the 1989 student movement were denied entry to Macau and Hong Kong, according to reports yesterday by the Associated Press and the South China Morning Post.

Wu’er Kaixi, the second most-wanted student leader during the protests, was denied entry yesterday to the southern Chinese city of Macau, AP reported. Xiang Xiaoji was denied entry into Hong Kong, the South China Morning Post said yesterday.

--Eugene Tang, William Bi, Dune Lawrence, John Liu and Sophie Leung. Editors: Matthew Brooker, Bill Austin.

To contact the reporter on this story: Mark Lee Wai Yee in Hong Kong at wlee37@bloomberg.net

Last Updated: June 4, 2009 06:06 EDT