A comic who called Puerto Rico garbage at a racism-ridden Donald Trump rally in New York has sparked an outburst of fury that could affect the US presidential election.

Puerto Ricans cannot vote in general elections, despite being US citizens – but they can exert a powerful influence with relatives on the mainland.

Phones across the island of 3.2 million people began ringing minutes after comedian Tony Hinchcliffe derided the US territory in a gig at Trump’s Madison Square Garden rally on Sunday night (local time). They were still buzzing on Monday.

Democratic Vice President Kamala Harris is competing with Trump to win over Puerto Rican communities in Pennsylvania and other swing states in next week’s US presidential election.

“I don’t know if you guys know this, but there’s literally a floating island of garbage in the middle of the ocean right now. I think it’s called Puerto Rico,” stand-up comic Hinchcliffe said at the packed Madison Square Garden.

Only minutes after the “joke” aired, Puerto Rican reggaeton superstar Bad Bunny announced he was backing Harris. Compatriot Ricky Martin posted a clip of the comments for his nearly 17 million followers on Instagram and wrote, in Spanish, “This is what they think of us.”

Hinchcliffe also went on to say of Latinos: “They love making babies too. Just know that. They do. They do. There’s no pulling out. They don’t do that. They come inside. Just like they did to our country.”

There were other lewd and racist comments about Jews and black people, all key constituencies in the US election.

“This is just a big punch in the gut for Republicans who have sincerely and over a period of time been working to grow strong relationships and roots in Puerto Rican communities, particularly here in the state of Florida,” former Florida House representative Carlos Curbelo said.

Hinchcliffe wasn’t the only one to bring out racist and otherwise offensive remarks at Sunday’s rally.

Conservative commentator Tucker Carlson called Harris a “Samoan, Malaysian, low-IQ former California prosecutor” – she is actually black and Indian American.

Trump’s former personal lawyer and long-time ally Rudy Giuliani – a former New York City mayor – took aim at Palestinians in his speech.

““They may have good people. I’m sorry, I don’t take a risk with people that are taught to kill Americans at two,” he said.

Milagros Serrano, 81, has a son who lives in the swing state of Pennsylvania and said his entire family was outraged by the Puerto Rican insults.

“He can’t be talking about Puerto Rico like that,” she said.

“He’s the one who’s a piece of garbage.”

Puerto Rico became a US territory in 1917. Its first large wave of migration to the mainland came after World War II to ease labour shortages.

There are now more Puerto Ricans in the US than on the island.

Those who stayed behind say they often feel like second-class citizens because they can’t vote in presidential elections and receive limited federal funding compared with US states.

That festering resentment erupted when Trump visited Puerto Rico after Hurricane Maria slammed into the island as a powerful category four storm in 2017.

He tossed paper towels into a crowd and denied the storm’s official death toll, with experts estimating that nearly 3000 people had died.

José Acevedo, a 48-year-old health worker from San Juan, shook his head as he recalled his feelings as he watched the rally.

“What humiliation, what discrimination!” he said early on Monday as he waited to catch a public bus to work.

Acevedo said he immediately texted relatives in New York, including an uncle who is a Republican and had planned to vote for Trump.

“He told me that he was going to have to analyse his decision,” Acevedo said, adding that his relatives were in shock.

“They couldn’t believe it.”

The Trump campaign has distanced itself from the inflammatory remarks. Spokesperson Karoline Leavitt told Fox & Friends that “it was a comedian who made a joke in poor taste”.

“Obviously, that joke does not reflect the views of president Trump or our campaign, and I think it is sad that the media will pick up on one joke that was made by a comedian, rather than the truths that were shared by the phenomenal list of speakers that we had,” she said.

Harris and President Joe Biden have both condemned the remarks.

“What he did last night is not a discovery. It is just more of the same, and maybe more vivid than usual,” Harris said.

“Donald Trump spends full time trying to have Americans point their finger at each other, fans the fuel of hate and division. And that’s why people are exhausted with him.”

Biden – who voted for Harris in Delaware on Monday (local time) – said the rally was embarrassing.

“It’s beneath any president, but that’s what we’re getting used to. That’s why this election is so important,” he said.

Hinchcliffe has defended his comments, accusing critics – who also included Harris’s running mate Tim Walz and New York Democrat Alexandria Ocasio-Cortez – of having “no sense of humour”.

-with AAP