The United States is set to scrap coronavirus border restrictions on Thursday night. The move could accelerate an influx of immigrants seeking asylum.
The number of Central and South Americans crossing into the US state of Texas, for example, has risen sharply ahead of the formal lifting of the pandemic regulations.
US Border Patrol agents have taken custody of some entrants in the border town of El Paso, Texas, and bused them to a facility to apply for asylum.
About 300 migrants have also gathered near a humanitarian support facility.
A facility official said he expects far more migrants will arrive once the restrictions are gone. The rules were aimed at preventing the spread of the coronavirus and made it much more difficult to seek asylum in the US.
The administration of US President Joe Biden has dispatched local National Guard forces and 1,500 military personnel to bolster security along the border.
Still, many migrants now in Mexico seem eager to enter the US. Former US President Donald Trump and other Republicans are accusing the Biden administration of causing a migrant crisis and are apparently trying to use it as a major issue for next year's presidential election.