Naco, Ariz. ? Volunteers recruited over the Internet to monitor illegal immigrant activity along a stretch of Arizona’s border ended their monthlong campaign this weekend as they began — peering through binoculars along a dusty border road.

Members of the Minuteman Project hailed the program as a success, and organizers said they plan to expand the mission to the other states bordering Mexico, and parts of the Canadian border.

“This could not have been done without all of you. You did this together — you the people,” co-organizer Chris Simcox told some 150 Minutemen and supporters gathered Saturday outside a church at Palominas.

Organizers said nearly 900 volunteers — some of them armed — had spent at least one eight-hour shift in the field through Friday, working mostly stationary patrols along a 23-mile stretch of border in Cochise County. The final eight-hour shift was scheduled to end at 6 a.m. today.

Organizers said volunteers’ calls to the Border Patrol resulted in the arrests of 335 illegal immigrants. Project organizers had ordered volunteers not to detain any illegal border crossers they encountered, and no major incidents were reported.

Critics of the program, including Border Patrol officials, have said the group was little more than a nuisance that attracted attention from the media and civil rights groups watching volunteers for possible rights violations.

Minuteman Project border volunteer and daylight crew supervisor Ed Whitbred from Maryland films over the U.S. Mexico border along Border Road on Saturday near Naco, Ariz.

President Bush expressed his opposition to “vigilantes,” and many people on the Mexican side of the border referred to the Minutemen as “migrant hunters.”

But Jim Gilchrist, founder of the program, said the group’s efforts brought nationwide attention to the problem of illegal immigration. He warned, however, that unless the work continues, “it’s going to be viewed as just a monthlong dog and pony show.”