Just hours before he arrived in China for the Beijing Olympics, the United States president George Bush expressed deep concerns over China's human rights record.
In Bangkok, Mr Bush praised China's economy but said only respect for human rights will let it realise its full potential.
Mr Bush voiced "firm opposition" to China's detention of dissidents, human rights advocates and religious activists.
He said the "United States believes the people of China deserve the fundamental liberty that is the natural right of all human beings."
Mr Bush said: "We speak out for a free press, freedom of assembly, and labour rights not to antagonize China's leaders, but because trusting its people with greater freedom is the only way for China to develop its full potential".
Australia's prime minister Kevin Rudd has also called on the international community to maintain pressure on Beijing over human rights.
But Mr Rudd says China's record has been improving.
He says the responsibility of the international community is still to speak with a strong, united voice on these questions, while recognising, over time, some progress has been made in China.