U.S. border officials on Sunday closed two rail bridges that move freight between Texas and Mexico after detecting a surge in the smuggling of migrants through Mexico by train.

The move by U.S. Customs and Border Protection was the latest in a series of similar closures along the border in order to redeploy enforcement resources elsewhere in response to large numbers of migrants.

The international railway crossing bridges in Eagle Pass and El Paso were closed "in order to redirect personnel to assist the U.S. Border Patrol with taking migrants into custody," CBP said in a statement.

"After observing a recent resurgence of smuggling organizations moving migrants through Mexico via freight trains, CBP is taking additional actions to surge personnel and address this concerning development, including in partnership with Mexican authorities," the statement said.

CBP has imposed similar temporary closures in recent weeks, shutting the Lukeville port of entry in Arizona, a pedestrian entrance in San Diego, and a vehicle crossing in Eagle Pass.

After the Lukeville closure, Arizona Governor Katie Hobbs on Friday ordered National Guard troops to the border with Mexico, saying the U.S. federal government's decision had put public safety and commerce at risk.