US President Joe Biden has placed Vice President Kamala Harris in charge of controlling an influx of young migrants at the country's southern border.
US media reports say more than 15,000 children from Central America are being held at the border due to a shortage of shelter facilities.
The media say the mass arrivals were triggered by the Biden administration's decision to allow unaccompanied minors into the US.
Biden told reporters at the White House on Wednesday, "This new surge we're dealing with now started with the last administration, but it's our responsibility to deal with it humanely."
Republicans described the border situation as inhumane and blamed Biden for overturning his predecessor's immigration policy.
Some of Biden's fellow Democrats have also called for action to stem the migrant flow.