"Were either side moving unilaterally to change the status quo, we oppose that, we don't want to see it, we think it's dangerous," said the official, who was authorized to brief reporters on the condition of anonymity. "We think anything that looks like a unilateral move towards independence on the part of Taiwan can start down a dangerous road."

Wen replied, "We very much appreciate the position adopted by President Bush," adding that Bush had voiced outright "opposition to Taiwan independence."

On other issues, Wen promised steps to cut the U.S.-China trade gap — which has ballooned this year to $120 billion in China's favor — and to continue to press North Korea to abandon its nuclear weapons program.

Both Bush and Wen cast the day's developments as reflective of the growing stakes in U.S.-Chinese relations.

"We are partners in diplomacy working to meet the dangers of the 21st century," Bush said during a South Lawn welcoming ceremony for Wen that included a 19-gun salute and the playing of both countries' national anthems by a U.S. military band.

Bush urged Wen to press for democratic reforms in China.

"The growth of economic freedom in China provides reason to hope that social, political and religious freedoms will grow there as well," said Bush. "In the long run, these freedoms are indivisible and essential to national greatness and national dignity."

The senior administration official said the United States remains committed to supporting a democratic Taiwan. The official drew a distinction between democracy in Taiwan — which held its first direct democratic presidential elections in 1996 — and Taiwanese independence, a sensitive issue for China, which has long said it would respond with military force to independence moves by Taipei.

"The president's top goal is preserving the peace in the Taiwan Strait," the official said, speaking on background. "We are in no way abandoning support for Taiwan's democracy or for the spread of freedom."

Bush reiterated to Wen earlier warnings echoing his March 2001 statement that the United States would do "whatever it took to help Taiwan defend herself" against any military action by China.

"The president did tell the Chinese in no uncertain terms that we, the United States, would have to get involved if China tried to use coercion or force to unilaterally change the status of Taiwan," the official said. "The president was very, very forceful on this issue."

The Taiwan issue is being played out amid another high-stakes diplomatic issue. Bush is relying on China's cooperation in efforts to persuade North Korea to dismantle its nuclear weapons program in exchange for security guarantees and economic aid from the United States and its East Asian partners.