Republican presidential candidate Donald Trump has headlined a rally at New York’s Madison Square Garden, delivering his campaign's closing argument with the election nine days away.

Trump, a New York resident for decades, hoped to use the event at the iconic venue known for basketball games and concerts to deliver his closing argument against Democratic candidate Kamala Harris, even though the state last backed a Republican presidential candidate in 1984.

“I’d like to begin by asking a very simple question. Are you better off now than you were four years ago?” Trump said at the start of his speech. The crowd shouted: “No.”

"This election is a choice between whether we will have four more years of gross incompetence and failure, or whether we will begin the four greatest years in the history of our country," Trump said.

He went on to promise that he would stop an “invasion of criminals coming into our country” if he wins the November 5 election.

The arena was full hours before Trump was scheduled to speak. Outside the arena, the sidewalks were overflowing with Trump supporters in red “Make America Great Again” hats. There was a heavy security presence. Streets were blocked off and access to Penn Station was restricted.

Donald Trump promises new tax cut for seniors. – AP

The list of at least 20 opening speakers varied widely from former pro wrestler Hulk Hogan to former New York mayor Rudy Giuliani to Trump’s sons Eric and Don Jr.

US billionaire Elon Musk, who is supporting Trump’s re-election bid, was greeted to the stage with chants of “Elon”.

“This is the kind of positive energy that America is all about,” Musk said.

Musk, who Trump has said he would tap to lead a new government efficiency commission, said the federal budget could be reduced by “at least” $2 trillion. Federal outlays topped $6.75 trillion in fiscal 2024, which ended September 30.

Trump got cheers inside the arena for his tough-on-migrants rhetoric. He vowed to ban sanctuary cities and invoke the 1798 Alien Enemies Act law to deport immigrants with criminal records.

Attendees cheer at Donald Trump's campaign rally at Madison Square Garden. – AP

Trump announced a new policy to provide a tax credit for family caregivers “who take care of a parent or a loved one”.

The closing message he delivered was that Harris “broke” the country and that he “will fix it”. Rallygoers hours beforehand waved signs with the words: “Trump will fix it.”

"I'm asking you to dream big again. We're going to dream big again. We haven't been dreaming big at all. This will be America's new golden age," Trump told his supporters.

"It's going to happen quickly too, very quickly. Every problem facing us can be solved, but now the fate of our nation is in your hands." 

Polls show the rival candidates are neck and neck in the battleground states that will decide the next president with just over a week until Election Day. More than 38 million votes have already been cast.

Elon Musk speaks at Madison Square Garden. – AP

Trump has been seeking to tie Harris to the Biden administration’s handling of immigration and the economy. 

The US economy has outperformed the rest of the developed world since the Covid crisis, and stock markets hit record highs this year. But high prices of food, utilities and housing have roiled voters, who believe the economy is headed in the wrong direction.

Trump, who held a rally in Long Island, New York, in September, has said he is making a play for the state. Ronald Reagan’s re-election was the last time New York backed a Republican for president. Democrat Joe Biden won the state in 2020 by 23 percentage points.

By staging the event in the world’s biggest media market, Trump could also help boost Republican candidates in New York congressional races. The state has seven competitive seats that could help determine whether the party holds onto the US House of Representatives next year.

It could also give Trump a boost in nearby northeastern Pennsylvania, a battleground state that has increasingly become home for New York commuters.

Donald Trump walks to the stage at Madison Square Garden. – AP

Meanwhile, Harris said that "we must not wake up the day after the election and have any regrets", capping a day of campaigning across the largest city in the crucial battleground state of Pennsylvania.

Energising voters in Philadelphia, a traditional Democratic stronghold, will be crucial for Harris’s hopes of beating Trump. Otherwise, she’ll struggle to overcome Trump’s advantages in Pennsylvania’s rural areas.

Harris began the day with the Black congregation at the Church of Christian Compassion.

Her next stop was Philly Cuts, a barbershop in West Philadelphia. Pennsylvania state representative Jordan Harris moderated a conversation with Harris about improving racial representation in education.

Harris then visited nearby Hakim’s Bookstore, which specialises in African American history.

Kamala Harris rallies Philadelphia voters. – AP

Harris earlier visited a Puerto Rican restaurant in Philadelphia to encourage people to vote. She posted a video on social media promising to “invest in Puerto Rico’s future” as president.

Harris, who held a rally in Atlanta on Thursday and in Houston on Friday, will hold another high-profile event with a speech on Tuesday on the National Mall in Washington, where she will highlight contrasts between herself and Trump.

“My internal polling is my instinct,” Harris said to reporters in Philadelphia when asked how the campaign is faring in its internal election projections.

“The momentum is with us,” she added.

After her neighbourhood Philadelphia stops, Harris plans to visit every battleground state in coming days, including a Wisconsin rally and concert and a Las Vegas event.