U.S. Department of Homeland Security Secretary Kirstjen Nielsen will visit Border Field State Park Tuesday to see the reinforcements added to the U.S. -Mexico border in anticipation of a caravan of Central American migrants.
The move was to prepare for the potential arrival of thousands of migrants heading toward the border in a caravan - and in response to those who have already arrived in Tijuana, officials said.
US President Donald Trump has characterised the migrant caravan as an "invasion" and has deployed thousands of US troops to the border.
Other bands of mostly Salvadorans followed, with a small group setting off on Sunday from San Salvador.
The shift would come as the military seeks to adjust to realities on the ground, where soldiers have spent days stringing miles of barbed concertina wire and some have said that they spent days waiting for assignments.
CBP said then that they would be closed "to install and pre-position port hardening infrastructure equipment in preparation for the migrant caravan and the potential safety and security risk that it could cause".
Between parties, the study found a clear divide, with the majority of Republicans (54 percent) branding the caravan a "major threat", while just 11 percent of Democrats and 28 percent of independents agreed.
"There's too many people", said protester Josefina Arangure.
At the same time, however, Murray said that most Americans also "feel that each migrant should be given the opportunity to state their case for entering the United States".
Trump had remained mostly silent about the caravan since the November 6 vote, but on Monday he posted a photo on Twitter showing a fence that runs from the beach in Tijuana into the ocean now covered with razor wire.
The commander of the mission told Reuters last week that the number of troops may have peaked, and he would soon look at whether to begin sending forces home or shifting some to new border positions.
He said 1,800 have been convinced so far to return to his country.
The 4,000 migrants, mainly from Honduras, have used WhatsApp text message groups as a way to organize and communicate along their journey to the California border, and DHS personnel have joined those groups to gather that information.
"They are causing crime and big problems in Mexico", Trump said, before telling migrants, "Go home!"
Tijuana Mayor Juan Manuel Gastelum has called the migrants' arrival an "avalanche" that the city is ill-prepared to handle, calculating that they will be in Tijuana for at least six months as they wait to file asylum claims.
Vice President Mike Pence falsely claimed 10 terrorists a day were being stopped at the southern border, and Trump repeatedly tweeted about the "invasion" of migrants and denied the deployment was a political stunt.