Donald Trump railed against illegal immigrants Wednesday and pledged to visit an Ohio town simmering with racial tensions fueled by his campaign's conspiracy theories, as Kamala Harris courted minority voters and relished a poll bump in key swing states.

The Republican ex-president, whose hardline anti-immigrant rhetoric has become a centerpiece of his election campaign, told a boisterous rally on New York's Long Island that he would visit Springfield "in the next two weeks."

Trump and his running mate J.D. Vance have repeatedly falsely claimed that immigrants from Haiti were eating residents' pets in the Ohio town, where schools and government buildings have faced bomb threats after their comments.

In fierce remarks on Wednesday, Trump described illegal immigrants as "animals" and gang members who were destroying Americans' way of life.

"We're going to take those violent people and we're going to ship them back to their country, and if they come back in, they're going to pay a hell of a price," he warned.

With the candidates effectively tied in the polls less than seven weeks before Election Day, the US Federal Reserve on Wednesday made news that may well impact the race. The central bank cut its key lending rate by half a percentage point, the first reduction since the onset of the Covid-19 pandemic.

The move, which sharply lowers borrowing costs for Americans, was well-received by Vice President Harris, who has looked to highlight her and President Joe Biden's economic record in her race against Trump.

She called it "welcome news for Americans who have borne the brunt of high prices," while Biden's White House said the rate cut marked a "moment of progress" for the US economy.

But in a potential setback for the Harris camp ahead of the November 5 election, the influential Teamsters union announced it would not endorse a presidential candidate in 2024.

The group had endorsed Democrats in every presidential election since 2000.

The powerful union's decision came minutes after Harris told the Congressional Hispanic Caucus Institute of her commitment to working Americans.

"We have to put the middle class first. We have to put the working class first, understanding their dreams and their desires and their ambitions," she told the group in Washington.

Harris leads in Pennsylvania

The Democratic nominee also said the United States must "reform our broken immigration system and protect our Dreamers," referring to the roughly half million undocumented immigrant youth currently protected by law.

"Understand we can do both," she said.

In New York, Trump hammered Harris, saying she failed to curb undocumented migration.

"Kamala will be known as your invasion president," he said.

Trump also warned he was formulating a plan, if he wins, to impose reciprocal tariffs on nations that tax US-made products.

"It will be called the Trump Reciprocal Trade Act," Trump said. "And if China or any other country charges us a 200- or 100- or 300-percent tax then we will charge (the same) tax in return.

"You charge us, we charge you."

With the election nearing, a new poll showed Harris with significant leads over Trump in swing states Pennsylvania and Michigan.

The surveys, conducted after the candidates' September 10 televised debate, suggest a post-showdown boost for Harris, widely perceived as having outperformed Trump on stage.

In the Quinnipiac University's polls of likely voters, Harris leads Trump 51 percent to 45 percent in Pennsylvania, and 50 to 45 percent in Michigan. A third Rust Belt state, Wisconsin, has Harris one percentage point ahead.

Trump leads narrowly in the so-called Sun Belt states of Arizona, Georgia, and North Carolina, according to an amalgam of polls on survey tracker RealClearPolitics.com.

It shows Harris barely ahead in battleground Nevada.

'Earn the vote'

Harris only became the Democratic Party's presidential candidate in July, after Biden ended his reelection bid following a disastrous debate performance against Trump.

The candidates were campaigning Wednesday following another tense moment in an already restive race, three days after a gunman appeared to have tried to assassinate Trump in Florida, a second such threat in as many months.

"God has now spared my life," Trump told the Long Island crowd. "Not once but twice."

He also insisted minority voters were backing him in substantial numbers, claiming: "We're at the highest level of Black support in the history of the Republican Party."

Harris, who is half Black and half Indian-American, said Tuesday she was "working to earn the vote" of African-American men, and not just assuming they would support her because she is Black.