The United States said Thursday that China's human rights record was getting worse as authorities step up efforts to stifle dissent, even though Beijing let a top activist leave for New York.

"In China, the human rights situation deteriorated, particularly the freedoms of expression, assembly and association," the State Department said in its annual human rights report for 2011.

"The government stepped up efforts to silence political activists and resorted to extralegal measures," it said.

The report was issued five days after China allowed one of its best-known activists, Chen Guangcheng, to go to New York to study. Chen had dramatically escaped house arrest and took refuge in the US embassy ahead of a long-planned visit to Beijing by Secretary of State Hillary Clinton.

Speaking after Clinton at the release of the human rights report, senior official Mike Posner said that the United States was "closely monitoring" Chen's case including allegations of retribution against his nephew in China.

Posner said that the United States was also concerned about dissidents such as writer and democracy advocate Liu Xiaobo, who is the world's only imprisoned Nobel Peace Prize winner, and Gao Zhisheng, a lawyer defending some of China's most vulnerable people who has virtually disappeared since his arrest in 2009.

"In the last several years, there's been a closing of space for human rights lawyers and activists in China," said Posner, the assistant secretary of state in charge of human rights.

Posner said that the resolution of the Chen case showed that the United States and China could make progress on human rights while at the same time taking up the gamut of other political and economic issues between the two powers.

"What was striking to me is that we had a very successful meeting while a human rights issue was being played out," Posner said.

US officials have been restrained in public comments on Chen, fearing the deal could collapse if Chinese authorities became annoyed. China's foreign ministry each year voices anger over the US rights report, describing it as interference.

Chen, a self-taught lawyer who has been blind since childhood, riled authorities by exposing forced abortions and sterilizations under China's one-child-only policy.

In the 2011 report, the State Department detailed concerns over the treatment of Chen including thugs' "severe" beatings of him and his wife and assaults against activists who came near his home in eastern Shandong province.

The report said that Chinese authorities have increasingly turned to house arrest, including of family members, and have tried to stifle public debate through rigid controls on the Internet.

It said that "abuses peaked around high-profile events," including visits of foreign officials, sensitive anniversaries and calls for street gatherings inspired by the wave of anti-authoritarian protests in the Arab world.

The report said that ethnically Tibetan areas were under "increasingly intense" control by Chinese authorities, who have carried out "severe repression" of core freedoms as well as "serious human rights abuses" including extrajudicial killings.

The report said that Chinese authorities' actions have fueled "increasingly desperate acts" by Tibetans, including a wave of self-immolation protests.

Posner said that the United States was "very concerned" about the treatment of Tibetans as well as of Uighurs, the mostly Muslim people in the northwestern region of Xinjiang.