Chief U.S. Magistrate Judge Gregory Wormuth began filing the dismissals late on Wednesday, ruling that migrants did not know they were entering the military zone in New Mexico and therefore could not be charged, according to court documents and a defense attorney.

Assistant Federal Public Defender Amanda Skinner said Wormuth dismissed trespassing charges against all migrants who made initial court appearances on Thursday. The migrants still face charges for crossing the border illegally.

"Judge Wormuth found no probable cause," Skinner said in an email.

New Mexico U.S. Attorney Ryan Ellison, who filed the first trespassing charges against migrants on April 28, did not immediately respond to a request for comment.

The so-called New Mexico National Defense Area was established in April along 180 miles of the border, and U.S. Army troops were authorized to detain migrants entering the area from Mexico.

A second buffer zone was set up in Texas this month. Secretary of Defense Pete Hegseth said in a social media post the military would continue to expand the zones to gain "100% operational control" of the border.

U.S. attorneys charged over 100 migrants with crossing the border illegally and trespassing in the military zones in New Mexico and Texas, and potential combined penalties were up to 10 years imprisonment, according to Hegseth.

But Wormuth pushed back against the charges for the migrants in New Mexico, ordering Ellison on May 1 to show proof they were aware they entered the military zone unlawfully.

Defense attorneys argued warning signs in the area were inadequate to inform migrants they were committing a crime, a position Wormuth agreed with.

"The criminal complaint fails to establish probable cause to believe the defendant knew he/she was entering" the military zone, Wormuth wrote in his orders dismissing charges.

The Department of Defense did not immediately respond to a request for comment.