With music blasting and flags flying, supporters of Donald Trump celebrated his barnstorming first 100 days back in office as they gathered in Michigan in a party-like atmosphere to see the US president speak.

"He's done a beautiful job," said seller Donna Fitzsimons, 65, as she arranged an array of Trump merchandise outside the venue — including special "I Was There!" badges to mark Tuesday's milestone.

Hundreds of people, many sporting Trump's iconic red baseball cap, erupted in sporadic cheers as Trump gave a 90-minute speech at Macomb Community College, just north of US carmaking hub Detroit and near the border of American friend-turned-foe Canada.

The event marked 100 hectic days in the White House dominated by an immigration crackdown, sweeping levies and a wider right-wing agenda that has pitted Trump against the US courts amid complaints of executive overreach.

"He's taken quick action on things," said janitor Kyle Murphy, 45, who praised Trump for "calling out wokeness" and the work of the so-called Department of Government Efficiency led by his billionaire ally Elon Musk.

Steve Camber, a 60-year-old retired nurse, agreed, "No one can do anything in 100 days that quickly. But I think he's doing really good, and DOGE is doing amazing things"

Trump's supporters, who danced to rock music in the gymnasium-style hall before the president arrived, broke into chants of "USA! USA!" after he walked on stage in his signature blue suit and red tie.

Speaking in front of a sign reading "The Golden Age," Trump whipped the crowd up as he touted his successes, from tackling illegal immigration to renaming the Gulf of Mexico.

"We're saving the American dream. We're making America great again and it's happening fast," Trump told the audience, which was mostly full but thinned out towards the back.

One of the biggest cheers came after a video was played showing migrants deported from the United States having their heads shaved by armed guards in El Salvador, which has agreed to accept US deportees.

At least one young man — Trump suggested over the microphone he was a "radical left lunatic" — was removed from the event to boos after a disturbance in the audience.

Dozens of protesters aligned with the Democrats also gathered opposite the venue, with some holding signs reading "I desist," local media showed.

Tuesday's event marked Trump's return to his campaign trail stomping grounds in blue-collar Macomb County, which helped him win the crucial swing state of Michigan.

'Love'

For some attendees, it was a historic chance to show their love for the Republican leader.

"Any opportunity to see our president is exciting for me," said Lisa Reeves, a 55-year-old decorator, who sported a glittery MAGA hat.

"We love President Trump and his family. We just love their heart for America and the morality that they have for this country," she added.

Still, some voiced reservations about Trump's actions, as opinion polls have shown a slump in support for the president since January.

Nelly Nkouka, 40, who moved to America from the Congo in 2005, said she liked that Trump was "honest" but was hesitant about his large-scale deportation of migrants.

"I think everybody needs a chance to be here," the care home supervisor said. "Somebody needs to talk to him about it, to let people have an American dream."

Zaid Hanif, 29, said he backed Trump's clampdown on the southern US border but was disappointed about his coziness with Israel, and his failure to make China concede in the countries' ongoing trade war.

Still, he was confident Trump could fix the economic turbulence triggered by his broad, stop-start tariffs policies that advocates say will boost American industry.

"Obviously the economy is not too good right now but to fix it, if you're not feeling well, you're going to take some medicine, and medicine doesn’t always taste the best," said Hanif, a textiles business owner.

Fitzsimons, the merchandise seller, agreed: "It takes time to get to where you need to go... Let it play out."