US President Barack Obama has told China that individual rights and freedoms should be available to all.
He told an audience of Chinese students that certain freedoms were universal - and not just limited to Americans.
Speaking at a question and answer session in Shanghai, Mr Obama added that China and the US were not destined to be adversaries.
He has now arrived in the Chinese capital, Beijing, where he is to meet President Hu Jintao.
Freedom of expression
In his speech at the Shanghai Science and Technology Museum, the US president praised China's efforts in lifting millions of people out of poverty, saying it was "unparalleled" in human history.
But according to a BBC correspondent in Beijing, Michael Bristow, Mr Obama also made comments that his hosts would have been less pleased to hear.
Although he was careful not to attack the Chinese government directly, he declared that certain rights and freedoms were universal.
China is an authoritarian country in which there are no elections for the country's national leaders. Media outlets and the internet are heavily censored, and those who speak out against the government are often imprisoned.
"We do not seek to impose any system of government on any other nation, but we also don't believe that the principles we stand for are unique to our nation," he said.
"These freedoms of expression and worship, of access to information and political participation - we believe are universal rights."
Mr Obama added: "They should be available to all people, including ethnic and religious minorities, whether they are in the United States, China or any nation."
After his main speech, he addressed the issue again in a question and answer session with Chinese students - many of whom spoke English.
Mr Obama said freedom of information - including open access to the internet - was important.
"That makes our democracy stronger because it forces me to hear opinions that I don't want to hear - it forces me to examine what I'm doing," he said.
He said the internet was a powerful tool to mobilise people and had helped him win the presidency last year.
Nobel prize
The US president said there was no reason that the United States and China - a "majestic" country - should not co-operate.
"We have known setbacks and challenges over the last 30 years. Our relationship has not been without disagreement and difficulty. But the notion that we must be adversaries is not predestined," he said.
The United States does not want to constrain China's rise, the US president added. He made a similar comment a few days ago in Japan.
Mr Obama's question and answer session included queries about Taiwan, the Nobel Peace Prize and cultural diversity.
The session was broadcast live on local Shanghai TV but was not carried live on national networks. The official Xinhua news agency posted a live transcript of his remarks.
The president then flew to Beijing to meet Chinese President Hu Jintao for dinner.
The two are expected to hold talks on Tuesday on issues such as trade imbalances, the nuclear programmes of Iran and North Korea, and the effort to tackle climate change.
President Obama is also expected to do some sightseeing while in Beijing, visiting the Great Wall of China and the Forbidden City, previously home to China's emperors.
Mr Obama is on his first trip to Asia as US president. He has visited Japan and Singapore, and is scheduled to fly to South Korea after leaving China.
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