UNIONDALE, N.Y. — Donald Trump's supporters started packing the Nassau Coliseum parking lot just after 8 a.m. on Wednesday in advance of the former president's scheduled rally later in the evening.

The doors opened at 3 p.m. and Trump hit the stage at 7 p.m.

Security was extraordinarily tight for Trump's first rally since Sunday's second assassination attempt. Measures were both seen and unseen, including visible sharpshooters and bomb-sniffing dogs, helicopters overhead, and undercover operatives in the crowd.

"For this event, we have to keep it airtight ... All working together, our federal, state and law enforcement and Homeland Security partners. This will be a very, very safe place," said Nassau County Executive Bruce Blakeman.

Read more: Suspect in apparent Trump assassination attempt hit with two gun charges

Police said earlier reports on social media of explosives being found at the site were false. They said one person, who may have been training a bomb-detection dog near the site, was detained and is being questioned.

Trump supporters out in force on Long Island

Nassau County Police Commissioner Patrick Ryder unlocked the gate at the coliseum himself, signaling the start of an event he vowed would be the safest place in the country.

First on line was Virginia Ciccotto of Massapequa park who overnighted outside the coliseum.

"He had everything right, we were doing great and now this country is falling apart. Everything is scary. It's dangerous," Ciccotto said.

Hundreds of people in red Make America Great Again caps waving flags poured in, reflecting belief New York state can be flipped.

"I expect President Trump to talk about the need to make life in this country more affordable, to strengthen our border, to be more energy independent and dominant, to have safer streets, better foreign policy and more," said former congressman Lee Zeldin.

"It's a great possibility because, President Trump, we know what we had with his first four years," one person said.

"People see the man delivers and with inflation, immigration, everything seems like it's upside down," another said.

"He's a wonderful guy. He has done so much for our country," said Matt Kay, of Brooklyn. "A lot of bad things have happened these last four years and Kamala is not the answer. It's Donald Trump."

"I keep meeting more people who think conservatively like I do, so I definitely feel like it could be one of the best chances that New York could go that direction," said Plainview resident Ari Gross.

Trump was invited by Nassau County Executive Bruce Blakeman, in part to bolster Republican congressional candidates in races that will help determine the balance of power in the House of Representatives.

"A lot of people are saying Trump is not good for Nassau, he's this, he's that. Look at these people. This is what we need again," one person said.

"We need him back. Look at the prices of gas and food and everything skyrocketing," one person said.

Anti-Trump protests held outside Nassau Coliseum

Reflecting the divisions in the country, large protests were expected just outside the gates of coliseum later Wednesday.

"Donald Trump, you know, he puts on a good show. Unfortunately, he puts on a crummy presidency," one man said. "So I think that's what we have to remind voters of. We're out here to remind voters that Donald Trump is really no good for Nassau County, no good for the state of New York state, and certainly no good for the United States of America."

Haitians gathered to blast the pet-eating rumors spread by Trump.

"We are calling on Haitians to stand up and vote versus Trump," Assemblyman Philip Ramos said.

Democratic leaders said Trump's visit means less time campaigning in swing states.

"New York is solidly blue, so I think it's a fantasy they're going to change the electoral vote," state Democratic Chairman Jay Jacobs said.

"Now [Trump] says he is for SALT deduction, but he is the author and pusher of this initiative to take away this tax relief," Assemblywoman Michaelle Solages said.

Trump speaks on Long Island, Second Gentleman Doug Emhoff campaigns for Harris in Brooklyn

In his 90-minute speech, Trump talked about the decay of the city he was born in and promised to reinstate the local tax deduction known as SALT, which his administration backed legislation to cap during his presidency.

"Saving thousands of dollars for residents of New York, Pennsylvania, New Jersey and other high-cost states," Trump said.

Even if he doesn't flip the state red, the former president was invited to Long Island by the Republican Nassau County executive in part to help bolster Republican congressional candidates.

"The House Republican majority absolutely comes through New York. It may not be there yet for the presidential race," Rep. Nick LaLota said.

"The political earth under us has moved to the right. We'll find out in November what that means for the New York electorate," Zeldin said.

Just a few miles away, Second Gentleman Doug Emhoff campaigned for his wife in Brooklyn.

"Look at how she stepped up in July. Look at how she stepped up at the convention. Look at how she stepped up at that debate," he said.

Speaking to the Congressional Hispanic Caucus in Washington earlier Wednesday, Vice President Kamala Harris vowed to cut taxes for working families and expand the child tax credit.

"It's not fair that our seniors have had to choose between filling their prescriptions and putting food in their refrigerator or paying their rent," Harris said.