Donald Trump has said undocumented immigrants were “poisoning the blood of our country” during a speech in New Hampshire.
The Republican presidential frontrunner repeated language that had previously been criticized as xenophobic and echoing Nazi rhetoric.
Mr Trump made the comments during a campaign event where he railed against the record number of migrants attempting to cross the US border illegally.
He has promised to crack down on illegal immigration and restrict legal immigration if elected to a second four-year term in office.
“They’re poisoning the blood of our country,” he told a rally in the city of Durham attended by several thousand supporters.
He said immigrants were coming to the US from Asia and Africa in addition to South America, adding: “All over the world they are pouring into our country.”
He used the same “poisoning the blood” language during an interview with The National Pulse, a right-leaning website that was published in late September.
It prompted a rebuke from the Anti-Defamation League, whose leader, Jonathan Greenblatt, called the language “racist, xenophobic and despicable”.
Jason Stanley, a Yale professor and author of a book on fascism, said Mr Trump’s repeated use of that language was dangerous.
He said the words echoed the rhetoric of Nazi leader Adolf Hitler.
“He is now employing this vocabulary in repetition in rallies. Repeating dangerous speech increases its normalization and the practices it recommends,” he said.
“This is very concerning talk for the safety of immigrants in the US.”
In October, Trump campaign spokesperson Steven Cheung had dismissed criticism of the former president’s language as “nonsensical”, arguing that similar language was prevalent in books, news articles and on TV.