Several hundred immigrants have been charged with unauthorized access to a newly designated militarized zone along the southern U.S. border in New Mexico and Western Texas since the Department of Justice introduced the new approach.

Cases of migrants caught in new military zones on the U.S.-Mexico border have been stalled over legal confusion, and lawyers and a U.S. senator on Wednesday raised concerns over whether people actually know when they are entering the zones.

Federal magistrate judges in New Mexico have started dismissing military-base trespassing charges against immigrants who cross the southern U.S. border through a newly designated national defense zone