0100 GMT March 25, 2018
In an annual report to the UN Human Rights Council, High Commissioner for Human Rights Zeid Ra'ad al-Hussein also took democracies to task for failing to respect basic rights, Reuters reported.
"In the United States, I am shocked by reports that many migrants intercepted at the southern borders, including children, are detained in abusive conditions — such as freezing temperatures — and that some young children are being detained separately from their families," he said.
"Detentions and deportations of long-standing and law-abiding migrants have sharply increased, tearing families apart and creating enormous hardship."
The administration of US President Donald Trump has also ended the Central American Minors Refugee and Parole Program, which offered adolescents and children “a lifeline to safety,” and ended Temporary Protected Status for hundreds of thousands of people.
"I deplore the continuing uncertainty about beneficiaries of the DACA program," Zeid said, referring to Deferred Action for Childhood Arrivals, which protects roughly 700,000 "Dreamers" — mostly young Hispanics — from deportation and lets them work.
The protections are due to start phasing out in March under Trump's move to end DACA, but Congress so far has failed to pass legislation to address the fate of the "Dreamers".
Zeid also expressed concern about US proposals that could "drastically reduce social protections," particularly for poorer Americans.
In many European Union (EU) countries the trend towards "racism, xenophobia and incitement to hatred" was now dominating the political landscape, as shown in Italy's recent election campaign, he said.
"I am deeply concerned about the current overriding focus of EU States on preventing migrants from reaching Europe, and rushing to deport many who do," Zeid added.
By pushing migrants back from its borders, the EU risked "subcontracting their protection" to states such as Libya, where they faced a real risk of torture, sexual violence and other serious violations, he said.