Former United States President Donald Trump has held his first campaign rally since surviving last week’s assassination attempt, delivering a fiery and rambling two-hour speech in which he lashed out at Democrats and repeated a string of false claims about immigration and election fraud.

The rally in Grand Rapids, Michigan, took place on Saturday amid heightened security as Trump’s speech marked a return to his usual campaign tactics of insults, false claims and offensive language.

The Republican nominee, who had called for national unity in the aftermath of the shooting, mocked Democratic President Joe Biden as feeble and compared former House Speaker Nancy Pelosi with a “dog”.

The crowd of thousands laughed and cheered as he called on them to “fight, fight, fight”, evoking the moment after his attempted assassination on July 13, when, bloodied and surrounded by Secret Service agents, he raised a fist in the air and shouted, “fight”.

Al Jazeera’s Phil Lavelle, reporting from Grand Rapids, said Trump’s supporters had come out in force to show their support for their candidate in Michigan, a crucial battleground state in the November election.

“For hours before this rally began, there were queues. People were lining up for miles,” Lavelle said. “Everybody I spoke to said we want to be here, we want to support Donald Trump, and a number of T-shirts hats have moved on from phrases like Make America Great Again to showing that picture of Trump with his fist raised in the air and those words – ‘fight, fight, fight’. Everybody here really wanted to get behind the former president.”

Insults, false claims

In his speech, Trump described Biden as a “stupid” and “low-IQ individual” and attacked Democrats, saying they wanted to kick the president off the ticket after he won their nominating contest.

“They have a couple of problems. Number one, they have no idea who their candidate is,” Trump said to laughter and jeers. “This guy goes and he gets the votes and now they want to take it away.”

Referring to Pelosi, Trump said, “She’s turned on him like a dog. She’s as crazy as a bed bug.” He also denigrated Vice President Kamala Harris as “crazy”.

Trump went on to repeat false claims of fraud during the 2020 election, which he lost to Biden, saying, “The radical left Democrats rigged the presidential election in 2020 and we’re not going to allow them to rig the presidential election in 2024.”

He called on voters to deliver a “landslide that is too big to rig” and warned those who voted early to “follow your vote”.

The Republican candidate also unleashed a litany of threats against undocumented migrants, decrying an “invasion” over the US border and again suggesting that Democrats were allowing it to happen in the hope of using their votes.

He also touted his relationships with world leaders such as China’s Xi Jinping, North Korea’s Kim Jong Un, and Hungary’s Viktor Orban. He called the Chinese president a “great guy” and said he received a “beautiful note” from him following the assassination attempt.

Al Jazeera’s Lavelle said the rally marked the first time Trump and Vance appeared together on the campaign stage. “Now it moves up from here and they’re going off in their own individual directions. So Donald Trump will go and host his rallies, JD Vance will go and host his own,” he said.

“This becomes a two-man campaign now where they both try to spread the MAGA message to as many people as they can ahead of that election in November.”

‘I took a bullet for democracy’

Trump’s return to the campaign trail comes as Biden remains in self-isolation after contracting COVID-19. Biden campaign spokesperson Michael Tyler told reporters during a conference call on Saturday that details of the president’s return will follow “as soon as we have the green light”.

Biden has insisted he is not quitting, and has attempted to turn the focus back towards Trump, saying that Trump’s acceptance speech at the Republican convention on Thursday showcased a “dark vision for the future.”

The Republican candidate pushed back against efforts to cast him as a threat to democracy and an extremist, even as he has vowed mass deportations and threatened retribution against his political enemies.

“They keep saying, ‘He’s a threat to democracy…’ Last week I took a bullet for democracy,” he said to rousing cheers.

Opinion polls suggest a tight race between Trump and Biden at a national level, but Biden trailing in the battleground states that will likely determine the winner. Meanwhile, the president, who is 81 years old, is facing increasing pressure to end his re-election bid following his poor debate performance last month.

Many Democrats fear Biden may not have a realistic path to victory and that the party needs a new candidate to take on Trump.

Arshad Hasan, a Democratic political strategist and the founder of Convey Communications, told Al Jazeera Trump’s speech “blew all the way through” calls from all sides of the political aisle for the lowering of the rhetoric in the wake of the assassination attempt against him.

“Trump and Vance have clearly gone on the negative. They’ve started characterising the Democratic Party in the least flattering, the most negative tone, and so we really didn’t have a cessation of an aggressive tone,” Hasan said.

He acknowledged the turmoil in the Democratic Party, but said it was not clear how Biden could be replaced at this late stage.

“There is quite a bit of discussion about whether or not he should stay on the top of the ticket. But as it is, this is the man who won every Democratic primary contest in every state and territory,” he said.

“The real discussion about this is … how would we decide with about 100 days for the election, who would be on the top of the ticket. That is where there isn’t a clear answer. If we wanted to change who is at the top of the ticket, Joe Biden, how would we do that? Biden is the one person who can make that decision. And so far he said he’s staying.”