"President Bush has repeatedly underscored his opposition to unilateral changes to the status quo by either Taipei or Beijing because these threaten regional peace and stability, U.S. national interests and Taiwan's own welfare," said State Department spokesman Sean McCormack in a daily press briefing.

In 2000 and 2004, Taiwan leader Chen Shui-bian pledged that he would not "declare independence, change the national title, push for inclusion of sovereignty themes in the constitution, or promote a referendum to change the status quo in regards to the questions of independence and unification," McCormack noted.

Chen's fulfillment of his commitments "is a test of leadership, dependability and statesmanship and of his ability to protect Taiwan's interests ... and to maintain peace and stability in the Strait," said McCormack.

"Rhetoric that could raise doubts about these commitments is unhelpful," the spokesman added.

Chen said at a gathering on Sunday that he wanted independence, a new constitution, development, and new names for local firms that use the word "China" in their title.

A Chinese official has lashed out at Chen's "Taiwan independence" remarks, saying it was another "dangerous" step towards secession.

"Chen was blatantly preaching secessionist ideas, another dangerous step towards Taiwan independence," a spokesman for the Taiwan Affairs Office of China's State Council said.

Chen's attempt to seek "Taiwan independence" through constitutional reform posed a huge threat to peace and stability across the Taiwan Strait and to the Asia-Pacific region at large, said the official.

Chinese people, including their compatriots in Taiwan, would firmly oppose any such attempts, he said.