Migrants hoping to apply for asylum in the US must put their names on a waiting list that already had 3,000-plus people on it before the caravan arrived.
U.S. border agents fired tear gas on hundreds of migrants protesting near the border with Mexico after some of them attempted to breach the fencing.
US Customs officials closed the entire San Ysidro crossing for several hours before dawn, installing additional layers of razor wire and concrete barriers.
The quickest path into the United States is not through mountains or canyons but through the front gates of the country's immigration bureaucracy.
A new surge in Central American families attempting to enter the United States is putting a strain on Border Patrol facilities and migrant shelters along the stretch of border that includes New Mexico.
Immigration policy changes are having less of an impact on border apprehension numbers than the security and economic needs of Central American migrants.
Border Patrol launched Operation Blazing Sands last month to deter illegal border crossings and thwart human smuggling attempts.
The arrest of a Border Patrol supervisor on allegations that he killed four women calls new attention to the agency's problems keeping rogue officers off its force.
Juan David Ortiz, a 10-year U.S. Border Patrol veteran, was arrested after the fifth woman escaped and found a state trooper.