The Justice Department is scaling back its Terrorism Information and Prevention System, or Operation TIPS, before it even begins, following criticism from civil liberties groups.
The program was initially to have been launched this month, but officials now have said it will not be put into effect until lawmakers can be consulted when Congress returns in September.
Members of Congress and civil liberties groups have criticized the plan's call for mail carriers, utility employees and truckers to alert authorities to suspicious behavior they encountered on the job.
Under revised plans Friday, Justice officials said Operation TIPS will involve only truck drivers, dock workers, bus drivers and others who are in positions to monitor places and events that are obviously public.