Former US president Donald Trump is seen on a screen during his campaign-style rally in Ohio, US, on Saturday Photo: AFP

Donald Trump held his first big campaign-style rally since leaving the White House, giving a vintage, rambling speech Saturday to an adoring audience as he launched a series of appearances ahead of next year's midterm elections.

The former president, who has been booted from social media platforms and faces multiple legal woes, has flirted with his own potential candidacy in 2024, but in the 90-minute address at fairground in Ohio, he made no clear mention of his political future, even when the crowd chanted "four more years! four more years!"

Trump did tease them at one point by alluding to the possibility of another stab at the White House.

"We may have to win it a third time. It is possible," he said, showing yet again he thinks he won in November. The crowd cheered wildly.

On other matters, Trump flitted from one to the next - immigration, crime, gun rights, Afghanistan, Iran and more - bouncing like a pinball in true Trumpian style.

One repeated message was that President Joe Biden is a catastrophe. "Joe Biden is destroying our nation before our very eyes," Trump said.

And Trump hammered away yet again at the falsehood that he won the November election but Biden prevailed through fraud. "The election was over," Trump said, "And we took a massive victory. They did into something that should never be allowed."

Until now, Trump had delivered two major speeches since leaving Washington in January, including a vindictive monologue in North Carolina early this month when he disputed his loss to Biden.

The Ohio rally drew a crowd of several thousand, who were enthusiastic but not quite raucous.

One purpose of it was for Trump to endorse conservative candidate Max Miller, a former Trump aide.

With this event, the brash billionaire made clear he wants to remain a powerful force in the Republican Party's effort to retake the Senate and House of Representatives next year.

In particular, he has signaled a willingness to help candidates who embrace his Make America Great Again movement.