"The position of China regarding the ABM treaty is clearcut and consistent," said a foreign ministry spokesman in Beijing.

"We hope that the US government will earnestly consider the position of the international community and act with prudence."

Bush on Thursday had vowed the United States would choose when to drop the key 1972 arms pact, which prohibits the kind of missile shield he says Washington will deploy to blunt attacks by so-called "rogue states".

"We will withdraw from the ABM treaty on our timetable," Bush said in Texas.

"I have made it clear that treaty hampers our ability to keep the peace, to develop defensive weapons necessary to defend America against the true threat of the 21st century," he added.

A signatory nation must give six months notice to withdraw, and US officials have said it is a matter of "months, not years" before efforts to develop the missile shield threaten to infringe the agreement.

China has consistently reiterated its support for maintaining the ABM treaty, and in July jointly signed an agreement with Russia pledging to back it.

Beijing furiously opposes even a limited shield which it fears could be used to defend Taiwan, which Beijing still views as a renegade province.