In a hard-hitting statement, UN High Commissioner for Refugees Zeid Ra'ad Al Husein said Katie Hopkins had used language similar to that employed by some Rwandan media outlets in the run-up to the 1994 genocide, and by the Nazis in the 1930s.
He said the April 17 article in Britain's best-selling paper was reflective of a "nasty underbelly of racism that is characterising the migration debate in an increasing number of EU countries".
This was also "sapping compassion for the thousands of people fleeing conflict, human rights violations and economic deprivation who are drowning in the Mediterranean," he said.
Already, more than 1,750 people have died this year making the perilous sea crossing to try to reach Europe -- 30 times higher than the same period in 2014.
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Zeid asked British authorities, media, and regulatory bodies to take immediate steps to stop racial and inflammatory articles.
"This vicious verbal assault on migrants and asylum seekers in the UK tabloid press has continued unchallenged under the law for far too long," he said.
"The Sun's editors took an editorial decision to publish this article, and -- if it is found in breach of the law -- should be held responsible along with the author."
He also asked all European countries to take a firmer line on racism and xenophobia.
Hopkins, in an article titled "Rescue boats? I'd use gunships to stop migrants", said the sight of dead floating bodies, coffins and "skinny people looking sad" left her cold.
"Make no mistake, these migrants are like cockroaches," she wrote. "They might look like 'Bob Geldof's Ethiopia circa 1984' but they are built to survive a nuclear bomb."
"Britain is not El Dorado," Hopkins said. "Some of our towns are festering sores, plagued by swarms of migrants and asylum seekers, shelling out benefits like Monopoly money.