U.S. Secretary of State Hillary Clinton says China should account for all people killed or missing from its 1989 crackdown on pro-democracy protests in Beijing.
Clinton issued the statement Wednesday on the eve of the 20th anniversary of the crackdown. China's government sent tanks and troops into Tiananmen Square on June 4, 1989 to crush weeks of student and worker protests, killing hundreds.
Secretary Clinton says China should examine what she calls the "darker events" of its past as it takes its place as a global power.
She urged Beijing to release dissidents still jailed in connection with the crackdown, end harassment of others and hold a dialogue with relatives of those killed.
Chinese security forces swarmed around Tiananmen Square Wednesday, examining visitors at checkpoints and barring access to journalists. Chinese authorities also forced several leading Chinese dissidents to leave Beijing and confined others to their homes.
Authorities in Macau detained a key student leader of the 1989 protests, Wu'er Kaixi, when he arrived in the southern Chinese territory Wednesday on a flight from Taipei.
Wu'er said he wants to enter mainland China through Macau to see his parents, whom authorities have barred from visiting him in Taiwan, where he lives in exile. He said Macau immigration officials refused to grant him entry and asked him to return to Taiwan.
In nearby Hong Kong, authorities deported another former student protest leader, Xiang Xiaoji, who flew into the territory from New York.
Xiang lives in exile in the United States and is a U.S. citizen. He had planned to attend an annual June 4 candlelight vigil in Hong Kong to remember those killed in the Tiananmen crackdown. The U.S. consulate in Hong Kong criticized his deportation.
China's government also has blocked access to social networking Web sites such as Twitter and foreign media reports to try to prevent discussion of the Tiananmen anniversary.
Rights group Amnesty International said Wednesday China's efforts to cut communication and prevent dissidents from moving will not stop people from marking the anniversary. It says excessive harassment will fuel the quest for truth about the crackdown.