Trump, who called for national unity in a speech on Thursday as he accepted his party's presidential nomination at the Republican National Convention, made no mention of that in his remarks before a raucous crowd of supporters in Grand Rapids.

He frequently mocked Democratic President Joe Biden as feeble. He derided senior Democrats, including Pelosi, for trying to persuade Biden to end his re-election bid.

Referring to Pelosi, Trump said: "She's turned on him like a dog. She's as crazy as a bed bug."

The Trump campaign did not immediately respond to a request for comment about Trump comparing Pelosi to a dog.

Fresh from his nominating convention where his takeover of the Republican Party was cemented, Trump appeared in Grand Rapids with his new vice presidential pick, Senator J.D. Vance from Ohio. They took the stage in their first campaign event together with the Republican Party unified behind them.

In contrast, it is no longer certain that President Joe Biden will be the Democratic Party's nominee facing Trump in the Nov. 5 election.

Biden has faced calls from some senior Democrats to end his re-election bid after his poor debate performance last month raised concerns over whether he could beat Trump or complete another four-year term.

Trump attacked Democrats, saying they wanted to kick Biden off the ticket after he won their presidential nominating contest.

"They have a couple of problems. No. 1, 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."

"As you're seeing, the Democrat Party is not the party of democracy. They're really the enemies of democracy."

He added: "And they keep saying, 'He's a threat to democracy.' I'm saying, 'What the hell did I do for democracy?'

Last week, I took a bullet for democracy."

Trump referred to the assassination attempt several times on Saturday. "I hope I don't have to go through that again. It was so horrible," Trump said.

Opinion polls show a tight race between the Trump and Biden at a national level but Biden trailing Trump in the battleground states that will likely determine the winner.

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

There was a heavy police presence at Trump's rally in Grand Rapids on Saturday, with police on every street corner for several blocks.

U.S. Secret Service officers were positioned on the top balconies in the Van Andel Arena, giving them a bird's eye view of the crowd inside.

Bag searches for those entering the indoor arena earlier in the day were long and thorough, and the Secret Service sweep of the building took about an hour longer than usual.

The rally in Butler, Pennsylvania, last weekend was outdoors. At that event, the gunman was able to scale the roof of a building outside the Secret Service perimeter before opening fire on Trump, clipping his ear, killing a rally-goer and wounding several others.

The Secret Service, which is responsible for protecting Trump, declined to comment on security for the Grand Rapids event. An investigation is under way into the security failures at the Butler rally.

Trump gave a detailed account of his narrow brush with death in his convention speech on Thursday, telling the audience that he was only talking to them "by the grace of Almighty God."

Trump's former physician, Ronny Jackson, said on Saturday that the former president is recovering as expected from the gunshot wound to his right ear, but noted intermittent bleeding and said Trump may require a hearing exam.

The bullet fired by the would-be assassin at the July 13 rally in Pennsylvania came "less than a quarter of an inch from entering his head," said Jackson, a Republican congressman from Texas who had served as physician to Presidents Trump and Barack Obama.