AP Photo/Kin Cheung
A screen showing the video of the 1989 student demonstrations in Tiananmen Square is seen from behind at a candlelight vigil at Hong Kong's Victoria Park on Thursday, June 4, 2009, to mark the 20th anniversary of the military crackdown on a pro-democracy student movement in Beijing.
AP Photo/Vincent Yu
Tens of thousands of people attend a candlelight vigil at Hong Kong's Victoria Park on Thursday, June 4, 2009, to mark the 20th anniversary of the June 4th military crackdown on the pro-democracy movement in Beijing's Tiananmen Square.
AP Photo/Vincent Yu
Melted candle wax is left on a newspaper with Chinese words reading "Insist rehabilitate June 4" as tens of thousands of people attend a candlelight vigil at Hong Kong's Victoria Park Thursday, June 4, 2009, to mark the 20th anniversary of the June 4th military crackdown on the pro-democracy movement in Beijing's Tiananmen Square.
AP Photo/Vincent Yu
A man walks past a poster featuring a man blocking a line of tanks at Hong Kong's Victoria Park on Thursday, June 4, 2009, where tens of thousands of people are expected to attend a candlelight vigil later in the evening to mark the 20th anniversary of the 1989 military crackdown on the pro-democracy movement in Beijing.
AP Photo/Kin Cheung
Protesters hold a wreath in memory of the victims of the June 4th Tiananmen Square crackdown as tens of thousands people stage a candlelight vigil at Hong Kong's Victoria Park on Thursday, June 4, 2009, to mark the 20th anniversary of the military crackdown on a pro-democracy student movement in Beijing.
AP Photo/Kin Cheung
People hold candles as tens of thousands people stage a candlelight vigil at Hong Kong's Victoria Park on Thursday, June 4, 2009, to mark the 20th anniversary of the military crackdown on a pro-democracy student movement in Beijing's Tiananmen Square.
CBS
People hold candles as tens of thousands people stage a candlelight vigil at Hong Kong's Victoria Park on Thursday, June 4, 2009, to mark the 20th anniversary of the 1989 military crackdown on a pro-democracy student movement in Tiananmen Square. Meanwhile, in Beijing, police had tightened security in the square and were not allowing foreign journalists to enter.
Beijing
AP Photo/Andy Wong
Chinese paramilitary police officers march past the Great Hall of the People after the flag-lowering ceremony at Tiananmen Square in Beijing, Thursday, June 4, 2009. Chinese police aggressively deterred dissent on the 20th anniversary of the crackdown on democracy activists in Tiananmen Square, ignoring calls from Hillary Rodham Clinton and even Taiwan's China-friendly president for Beijing to face up to the violence.
AP Photo/Elizabeth Dalziel
A paramilitary soldier stands guard at Tiananmen Gate, opposite to Tiananmen Square, in Beijing on Thursday, June 4, 2009. Foreign journalists were barred from the vast square Thursday as uniformed and plainclothes police stood guard across the vast plaza that was the epicenter of the student-led movement that was crushed by the military on the night of June 3-4, 1989.
AP Photo/Elizabeth Dalziel
Paramilitary soldiers patrol the area near Tiananmen Gate, opposite to Tiananmen Square, in Beijing on Thursday, June 4, 2009. Foreign journalists were barred from the vast square as uniformed and plainclothes police stood guard across the vast plaza that was the epicenter of the student-led movement that was crushed by the military on the night of June 3-4, 1989.
AP Photo/Elizabeth Dalziel
Plainclothes policemen shield themselves with umbrellas as they work undercover opposite to Tiananmen Square in Beijing, Thursday, June 4, 2009. Chinese police aggressively deterred dissent on the 20th anniversary of the crackdown on democracy activists in the square, ignoring calls from Hillary Rodham Clinton and even Taiwan's China-friendly president for Beijing to face up to the violence.
AP Photo/Elizabeth Dalziel
Paramilitary police and plainclothes soldiers patrol Tiananmen Square in Beijing, China, Thursday, June 4, 2009. Foreign journalists were barred from the vast square as uniformed and plainclothes police stood guard across the vast plaza that was the epicenter of the student-led movement that was crushed by the military on the night of June 3-4, 1989.
AP Photo/Elizabeth Dalziel
Paramilitary soldiers patrol on Tiananmen Square in Beijing Thursday, June 4, 2009. Foreign journalists were barred from the vast square Thursday as uniformed and plainclothes police stood guard across the vast plaza that was the epicenter of the student-led movement that was crushed by the military on the night of June 3-4, 1989.
AP Photo/Andy Wong
A Chinese paramilitary policeman, right, stands watch near Tiananmen Square, seen behind a police van, in Beijing, on Thursday, June 4, 2009. Police saturated the square with security on Thursday's 20th anniversary of the bloody crackdown on pro-democracy activists, and an exiled protest leader was blocked from returning home to confront Chinese officials over what he called the "June 4 massacre."
AP Photo/Elizabeth Dalziel
Cyclists ride by a near-deserted Tiananmen Square in Beijing on Wednesday, June 3, 2009. Foreign journalists were barred from the square, while authorities blocked Web sites such as Twitter and confined dissidents to their homes or forced them to leave Beijing. The efforts aim to prevent commemorations of the protests or remembrances of the hundreds, possibly thousands, who died in the June 3-4, 1989, military assault.
AP Photo/Elizabeth Dalziel
Chinese honor guard soldiers march against the backdrop of Tiananmen Square and Tianamen Gate in Beijing on Wednesday, June 3, 2009. Foreign journalists were barred from the square, while authorities blocked Web sites such as Twitter and confined dissidents to their homes or forced them to leave Beijing in order to prevent commemorations of the June 3-4, 1989, protests.
AP Photo/Elizabeth Dalziel
Chinese honor guards stand in position against the backdrop of Tiananmen Square and Tianamen Gate in Beijing on Wednesday, June 3, 2009. Foreign journalists were barred from Beijing's Tiananmen Square on Wednesday amid heavy security on the eve of the 20th anniversary of the bloody crackdown on 1989 pro-democracy protests.
AP Photo/Andy Wong
Chinese paramilitary police officers stand guard during a flag-lowering ceremony near Tiananmen Square in Beijing, Wednesday, June 3, 2009. Foreign journalists were barred from Beijing's Tiananmen Square on Wednesday as police fanned out across the vast plaza on the eve of the 20th anniversary of the bloody crackdown on 1989 pro-democracy protests.
AP Photo/Elizabeth Dalziel
Chinese honor guards stand in position next to Tiananmen Square in Beijing on Wednesday, June 3, 2009. Foreign journalists were barred from the square on Wednesday amid heavy security on the eve of the 20th anniversary of the bloody crackdown on 1989 pro-democracy protests.
AP Photo/Elizabeth Dalziel
Chinese honor guards stand in position against the backdrop of Tiananmen Square in Beijing on Wednesday, June 3, 2009. Foreign journalists were barred from the square on Wednesday amid heavy security on the eve of the 20th anniversary of the bloody crackdown on 1989 pro-democracy protests.