Rebiya Kadeer was greeted by supporters in Washington
An ethnic Uighur woman imprisoned by China since 1999 has arrived in the US after being freed from jail.
Rebiya Kadeer, 58, from China's western Xinjiang province, was detained after sending newspaper clippings to her husband in the US.
The release, described as a high priority for Washington, comes ahead of a visit to China by US Secretary of State Condoleezza Rice.
The White House has urged China to release all prisoners of conscience.
Correspondents say the decision to release Mrs Kadeer is a concession to the US in advance of Ms Rice's visit.
In return, White House spokesman Scott McClellan said the US would not table a resolution critical of China at the United Nations Human Rights Commission, which is meeting in Geneva.
He said China had made some progress towards improving human rights.
US state department spokesman Adam Ereli said these included allowing those convicted of political crimes the same rights to parole and sentence reduction as other prisoners.
China has also agreed to allow UN rights officials to visit, and to let the International Committee of the Red Cross open a Beijing office.
Ethnically Turkic Muslims, mainly in Xinjiang
Made bid for independent state in 1940s
Sporadic violence in Xinjiang since 1991
Uighurs worried about Chinese immigration and erosion of traditional culture
But human rights groups, while welcoming the release, said other Uighur prisoners of conscience remained in prison.
"Rebiya Kadeer's release does not alter the laws and practices regularly used by the Chinese authorities to detain and imprison individuals who peacefully exercise their rights," said Catherine Baber of Amnesty International.
A prominent member of the Uighur ethnic minority in China's north-west Xinjiang province, Mrs Kadeer was arrested in 1999 and convicted in 2000, accused of passing information to foreigners, separatism and attempting to overthrow the state.
According to transcripts, her trial centred on local newspaper clippings on the treatment of Uighurs that she had sent to her husband in the US.
China is intolerant of any dissent in the sensitive border region of Xinjiang, and is worried about several groups it brands as separatists.
Arriving in Chicago on Thursday evening, Mrs Kadeer declared: "From this time on, I am free."
News of her release had not reached Xinjiang, she said. "Nobody in the Uighur region knew I was free and leaving."
Before her arrest, Mrs Kadeer had been held up as a role model to China's large Muslim population.
She had owned a prosperous department store and started a charity helping other Muslim women find work.
She had even been appointed to a seat on one of the Chinese government's highest consultative bodies.
But China's Communist authorities changed their stance after her Uighur husband, a former political prisoner Sidik Rouzi, fled China for the US in 1996