Annexed militarized zones will soon cover nearly one-third of the U.S. border with Mexico, empowering soldiers to arrest people who cross the border illegally

The fourth national defense area created along the US-Mexico border will be an extension of Marine Corps Air Station Yuma in the Sonora Desert.

The Pentagon is establishing a fourth military defense zone along the U.S.-Mexico border, where American soldiers can apprehend noncitizens on charges of trespassing, Chief Pentagon spokesman Sean Parnell said Wednesday.