China is lashing out at the U.S. Congress over a bill that would reduce barriers to contact with Taiwan. The spokesman for the Cabinet's Taiwan Affairs Office, An Fengshan, on Friday said the bill violates the ``one-China principle'' under which Beijing regards Taiwan as a part of Chinese territory. The U.S. cut formal ties with the self-governing island democracy when it recognized China in 1979 but the two maintain robust unofficial relations. China threatens to use force to bring Taiwan under its control. The Senate on Wednesday unanimously passed the Taiwan Travel Act allowing unrestricted travel by U.S. officials to meet with members of Taiwan's government. Taiwanese officials would be able to visit the U.S. under ``respectful conditions'' and meet their counterparts, including from the Departments of State and Defense.