The United States closed off northbound traffic for several hours at the busiest border crossing with Mexico to install new security barriers on Monday, a day after hundreds of Tijuana residents protested against the presence of thousands of Central American migrants.
The U.S. also closed one of two pedestrian crossings at the San Ysidro crossing in a move apparently aimed at preventing any mass rush of migrants across the border.
The installation of movable, wire-topped barriers threatens to complicate life for Mexicans using San Ysidro, where about 110,000 people enter the U.S. every day in 40,000 vehicles.
Long lines backed up in Tijuana, where many people have to cross the border to work on the U.S. side.
Some Tijuana residents supported the migrants, but others accused them of being messy, ungrateful and a danger to the city.
The migrants' expected long stay in Tijuana has raised concerns about the ability of the border city of more than 1.6 million people to handle the influx.