The United States opposes any unilateral measures to change the status quo across the Taiwan Straits, acting spokesman of U.S. State Department Tom Casey said on Monday.

"We believe the maintenance of Taiwan's assurances is critical to preserving the status quo and our firm policy is that there should be no unilateral changes to the status quo," Casey told a regular press conference.

Casey reaffirmed the position when asked whether the United States had any concern over Taiwan leader Chen Shui-bian's pledge in an interview with Japan's Yomiuri Shimbun on Friday to draft for Taiwan a "new constitution based on legal procedures."

Chen declared on Feb. 27 that "the National Unification Council" would "cease to function" and that "the National Unification Guidelines" would "cease to apply."

"The National Unification Council" was set up in 1990 by the Taiwan authorities headed by Lee Teng-hui. "The National Unification Guidelines" were issued in 1991, saying that both the Chinese mainland and Taiwan are under the sovereignty of China and the promotion of the state's reunification should be the common task of all Chinese.

Source: Xinhua