BANGKOK, Thailand (CNN) -- U.S. President George W. Bush expressed "deep concerns" over religious freedom and human rights in China on the eve of the 2008 Beijing Olympics in a wide-ranging Asian policy speech delivered Thursday in Bangkok, Thailand.

"We speak out for a free press, freedom of assembly, and labor 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," he said. "And we press for openness and justice not to impose our beliefs but to allow the Chinese people to express theirs."

Despite the harsh critique, Bush praised what has become a "constructive relationship" between the United States and China in trade and diplomacy. He also said that the association "has placed America in a better position to be honest and direct on other issues."

Bush spoke at the Queen Sirikit National Convention Center in Bangkok.

The trip to Asia is Bush's last as president, and he took the opportunity to shine a light on the well-publicized crackdowns on political dissenters in the "people's republic" -- a communist country that has emerged as a symbol of soaring capitalistic growth.

"I have spoken clearly, candidly, and consistently with China's leaders about our deep concerns over religious freedom and human rights," he said. "And I have met repeatedly with Chinese dissidents and religious believers. The United States believes the people of China deserve the fundamental liberty that is the natural right of all human beings."

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China cracked down on protests this year in Tibet. Some demonstrators advocated autonomy and greater religious freedom there while others sought outright independence from China.

On Wednesday, four Tibet activists unfurled Tibetan flags and pro-independence banners near National Stadium in Beijing, a main Olympic venue.

Two men in the group scaled electric poles to display the banners, police said, according to the state-run Xinhua news agency. Police took away "four foreigners" -- three men and a woman, it said.

Students for a Free Tibet, a Tibet activist group, issued a statement saying those involved in the demonstration were from the United States and Britain.

According to the group, one of the signs read, "One World, One Dream: Free Tibet" in English, while the second read, "Tibet Will Be Free" in English and "Free Tibet" in Chinese.

The group said the signs were on display for about an hour, but police said it was about 12 minutes. The demonstrators entered China on tourist visas, police said, according to Xinhua.

Meanwhile, the government's reaction to people protesting in northwestern China's Xinjiang Uygur Autonomous Region, home to a Sunni Muslim ethnic minority, also has generated concerns. The Uygur people in that region are supposed to enjoy autonomy, guaranteed by China's constitution, but some seek independence.

Millions of Han Chinese, the country's dominant ethnic group, have migrated into Xinjiang over the past 60 years, prompting complaints that they dominate local politics, culture and commerce at the Uygurs' expense.

In the Xinjiang city of Kashgar, Chinese paramilitary police beat two Japanese journalists Monday night, hours after a deadly attack that killed 16 police officers, journalist groups said.

China has also been widely criticized for its policies toward Sudan. It has been perceived as backing the African regime and widely accused of gross human rights abuses in a crackdown against citizens in the Darfur region after a rebellion in 2003. The United States has condemned the campaign of killing in Darfur as genocide.

Team Darfur, a group of athletes committed to raising awareness about Darfur, complained that former speedskating gold medalist Joey Cheek had his visa revoked by the Chinese Embassy.

She said U.S. diplomats are asking the Chinese to reconsider their actions and emphasized that the administration hopes China changes its mind.

In Thursday's speech, Bush also focused on other issues, including the economic strides in China -- which endured "rampant" poverty three decades ago.

Beijing is "sprinting into the modern era -- covered in skyscrapers, filled with cars, home to international businesses, and hosting the Olympic Games," Bush said.

He said the "growth sparked by China's free market reforms is good for the Chinese people" and that "China's new purchasing power is also good for the world, because it provides an enormous market for exports from across the globe."

Bush urged China to adhere to the "rules of the international economic system" and "act responsibly on issues such as energy, the environment and African development."

He said the United States and China are embarking on "a new strategic economic dialogue," saying they will "discuss ways to ensure long-term growth and widely shared prosperity in both our economies, as well as issues like currency exchange rates and intellectual property rights."

Bush cited two areas of diplomatic cooperation -- the six-party talks on North Korea's nuclear program and the easing of tensions along the Taiwan Strait.