The statement called on the U.S.to adopt "adopt non-custodial alternatives that allow children to remain with their families and fulfil the best interests of the child, their right to liberty and their right to family life".
The UN human rights office said it was deeply concerned over the zero tolerance policy introduced by the Trump administration to deter illegal immigration. But it has ratified similar conventions, which means the country has legal obligations to all children in "it's care", explained Shamdasani.
William Spindler, of the UN refugee agency, said "the right to claim asylum is a fundamental human right. and it is also part of the law in the United States".More news: GOP's Cox faces tough slog in race for California governor
"Once again, the United Nations shows its hypocrisy by calling out the United States while it ignores the reprehensible human rights records of several members of its own Human Rights Council", said Nikki Haley, United States Ambassador to the United Nations.
"It is therefore of great concern that in the USA, migration control appears to have been prioritized over the effective care and protection of migrant children".
Also on Tuesday, NBC reported that "border agents and child welfare workers are running out of space to shelter children who have been separated from their parents", and that out of the 550 children who have now been held longer than 72 hours, 300 were under the age of 12.More news: France plans to ban mobile phones at school
The Trump administration will soon begin fingerprinting parents claiming custody of children who entered the United States illegally without an adult relative, officials said a week ago, prompting criticism that children may be abandoned by those who fear being identified and deported.
Peter Boogaard, a former DHS and White House official in the Obama administration and now a spokesman for immigration reform group FWD.us says these children having nowhere to go and being away from their parents is not entirely the fault of HSS. "Border Security laws should be changed but the Dems can't get their act together!", he said. But in a tweet, Trump, who demanded the separation policy be enforced at the beginning of May, blamed opposition Democrats for it. In April, the New York Times estimated that more than 700 children had been taken from parents or guardians in the prior six months, and NBC News estimates that there are now 550 children in custody at the border. Half of those children are under 12 years-old.More news: DOJ and FBI Offer More Spygate Details to Bipartisan Congressional Leaders