The US military has been asked to prepare to house 20,000 immigrant children as President Donald Trump rolls back his policy of separating them from parents at the border.
While no decision has been made, the US Department of Health and Human Services (HHS) had already assessed three military bases in Texas and would review another in Arkansas, Pentagon spokeswoman Dana White said.
She said HHS had asked the Pentagon "to determine its capabilities to provide up to 20,000 temporary beds for unaccompanied alien children" at military installations."
Ms White did not give further details and it was not clear how many of the children who could be sent to the bases were already being detained at other facilities.
Mr Trump and his administration faced fierce criticism in recent weeks for maintaining a staunch stance on his policy to separate children from their families to prosecute their parents for crossing the border illegally.
More than 2300 children were affected by the policy.
Video footage of children sitting in cages and an audiotape of wailing children sparked worldwide anger.
Mr Trump backed down on Wednesday, signing an executive order to keep families together in detention during immigration proceedings.
However, some legal experts said the wording of the executive order was ambiguous and that family separations could continue.
It remained unclear late on Thursday how and when those children would be reunited with their parents, or where families would be held while the parents faced criminal charges.
It was also not clear if the government would keep prosecuting cases against people caught crossing the border illegally, nor how Mr Trump's administration would handle new immigration cases on the border.
The administration said it would stick to a "zero tolerance" policy that meant anyone crossing illegally would be prosecuted.
While prosecutors said they were not dismissing any cases, some hearings on Thursday did not proceed as scheduled. In McAllen, Texas, 17 migrants were told by their public defenders that their cases were not proceeding for now.
Before one deportation flight left for Honduras from Texas on Thursday, US officials asked which passengers had children in detention in the US.
Deportees arriving in Honduras told Reuters the four who put up their hands were not put on the flight.
First Lady Melania Trump on Thursday flew to Texas to visit children displaced by the immigration crisis.
But the hooded, olive-green jacket she wore as she boarded the plane for Texas - daubed with the words "I REALLY DON'T CARE, DO U?" on the back - appeared to undercut the message of compassion.
The White House responded to criticism by saying there was no hidden message.
"It's a jacket," Mrs Trump's spokeswoman Stephanie Grisham said.
"After today's important visit to Texas, I hope the media isn't going to choose to focus on her wardrobe."
The president said, however, the message was directed at news organizations, which he dubbed the "Fake News Media".
'Human rights mess'
Mr Trump made cracking down on illegal immigration a key part of his presidential campaign in 2016, but his recent policies have upset many lawmakers inside his own Republican Party.
Mike Coffman, a Republican in the House of Representatives, called on Mr Trump to fire senior White House adviser Stephen Miller, who had pushed for a hardline approach to immigration.
"This is a human rights mess. It is on the President to clean it up and fire the people responsible for making it," Coffman said.
Mr Trump could face renewed criticism if thousands of immigrant children were soon sent to be housed on military bases.
It would not be the first time for such an arrangement.
The Obama administration set up temporary emergency housing at three military bases in 2014, as a wave of unaccompanied children mostly from Central America arrived at the US-Mexico border.
On Wednesday, US Defense Secretary Jim Mattis said the Pentagon would not lead such a mission, but would help if requested.
"We have housed refugees. We have housed people thrown out of their homes by earthquakes and hurricanes. We do whatever is in the best interest of the country," Mr Mattis told reporters.
- Reuters