Photo: The Canadian Press

Detainees at a facility in McAllen, Texas.

An unapologetic President Donald Trump defended his administration's border-protection policies Monday in the face of rising national outrage over the forced separation of migrant children from their parents. Calling for tough action against illegal immigration, Trump declared the U.S. "will not be a migrant camp" on his watch.

Images of children held in fenced cages fueled a growing chorus of condemnation from both political parties, four former first ladies and national evangelical leaders. The children are being held separately from parents who are being prosecuted under the administration's "zero-tolerance" policy for illegal border crossings.

Trump on Monday blamed Democrats for obstructing legislation to fix the situation. In fact, it was Trump's administration that broke with longstanding practice of processing migrant families in civil, rather than criminal, proceedings that allow families to be held together.

"I say it's very strongly the Democrats' fault," Trump said Monday as his administration rejected criticism that the policy has resulted in inhuman and immoral conditions.

Homeland Security Secretary Kirstjen Nielsen said, "We will not apologize for the job we do or for the job law enforcement does, for doing the job that the American people expect us to do."

In an appearance before the National Sheriffs' Association in New Orleans, Nielsen said: "Illegal actions have and must have consequences. No more free passes, no more get out of jail free cards."

Nearly 2,000 children were separated from their families over a six-week period in April and May after Attorney General Jeff Sessions announced the new "zero-tolerance" policy that refers all cases of illegal entry for criminal prosecution. Prior procedure had limited prosecution for many family entrants, in part because regulations prohibit detaining children with their parents since the children are not charged with a crime and the parents are.

The policy change was meant to deter unlawful crossings — and Sessions issued a warning last month to those entering the U.S. illegally that their children "inevitably for a period of time might be in different conditions."

The current holding areas have drawn widespread attention after journalists gained access to one site Sunday. At a McAllen, Texas, detention centre hundreds of immigrant children wait in a series of cages created by metal fencing. One cage had 20 children inside. Scattered about are bottles of water, bags of chips and large foil sheets intended to serve as blankets.

Audio of sobbing children calling out for their parents dominated the discussion Monday. "Papa! Papa!" one child is heard weeping in an audio file that was first reported by the non-profit ProPublica and later provided to The Associated Press.

Administration officials said they do not like the family separations either — calling it the result of legal loopholes — but insist migrants who arrive illegally simply won't be released or loosely kept track of.

"The United States will not be a migrant camp and it will not be a refugee holding facility," Trump declared. "Not on my watch."

Sessions, on Monday, echoed the administration's defence of the zero tolerance policy, and called on Congress to act.

"We do not want to separate parents from their children," he said. "If we build the wall, if we pass legislation to end the lawlessness, we won't face these terrible choices."