Donald Trump said Monday that illegal immigrants were bringing “bad genes” into the United States, doubling down on previous inflammatory rhetoric about migrants poisoning the blood of the country.

Trump was criticizing his Democratic presidential rival Vice President Kamala Harris in a radio interview when he brought up government figures showing there were 13,000 immigrants in the United States who were not in federal immigration detention, despite homicide convictions. 

“How about allowing people to come to an open border, 13,000 of which were murderers, many of them murdered far more than one person? They are now happily living in the United States,” he told conservative host Hugh Hewitt.

“You know now, a murderer — I believe this — it’s in their genes. We’ve got a lot of bad genes in our country right now. They had 425,000 people come into our country that shouldn’t be here that are criminals.”

Trump was misconstruing data released in September by the Immigration and Customs Enforcement (ICE) agency.

The figures don’t include people incarcerated outside of ICE facilities — in state, local or other federal facilities, for example — and they cover a period spanning decades, including when Trump was president.

US media reported Monday that migrant apprehensions at the US-Mexico border fell 75 per cent year-on-year in September — to the lowest level since the Trump administration — citing Department of Homeland Security statistics.

“I don’t normally defend Trump’s statements, and even here he drops the 13,000 released murderers lie,” said conservative political commentator Richard Hanania, president of the Center for the Study of Partisanship and Ideology.

“But he’s right that crime is largely genetic. He should just learn about the low crime rate among immigrants and think about the implications.”

Trump, who is neck-and-neck with Harris in nationwide and swing-state polling ahead of November’s election, has spent much of his campaign demonizing both undocumented immigrants and those in the United States legally. 

During a rally last month, the 78-year-old former reality TV star said Harris should be prosecuted over President Joe Biden’s border policies and called illegal immigrants “animals,” out to “rape, pillage, thieve, plunder and kill.”

“They will walk into your kitchen, they’ll cut your throat,” he said.

And he repeatedly threatened legal Haitian residents in Ohio with deportation, falsely accusing them of eating locals’ pets. 

Trump — the oldest major-party White House candidate in history and the first convicted felon to run — accused immigrants of “poisoning the blood of our country” in December in a phrase that earned him comparisons with Adolf Hitler.