The Bush administration has refused to give ground to critics of the controversial Patriot Act, saying that all the provisions of the act, which is due to expire at the end of this year, must be made permanent.

In his first testimony on the legislation, Alberto Gonzales, the new attorney-general, said yesterday that new powers given to investigators under the act "have proven to be essential weapons in our arsenal to combat the terrorists, and now is not the time for us to be engaging in unilateral disarmament".