Michael King, a member of American Border Patrol, a citizen watchdog group, rides along US-Mexico border

A citizen group is wrapping up a month-long effort to monitor illegal immigrants crossing one section of the U.S.-Mexico border.

The Minuteman Project plans to stop monitoring illegal immigrant activity in southern Arizona by Sunday, but says it will soon expand its program to other parts of the U.S. border.

The volunteers say they have prevented illegal immigrants from entering the United States by reporting their location to authorities.

Their efforts have drawn protests from human rights groups and Mexico's government.

Some information for this report provided by AP.