President Donald Trump said on Wednesday he is "not allowed" to run for a third term, acknowledging the limits laid out in the US Constitution.

Trump and his supporters have repeatedly raised the question of a 2028 presidential run for the 79-year-old, drawing concern from his foes and cheers from backers.

"I have my highest poll numbers that I've ever had and, you know, based on what I read, I guess I'm not allowed to run, so we'll see what happens... It's too bad," Trump said on Air Force One.

The US Constitution limits presidents to two terms, and Trump began his second in January.

'A lot of great people'

Trump, who served his initial term from 2017 to 2021, often mentions that his supporters have called for him to govern beyond his current tenure despite the constitutional restriction.

The president has also recently displayed red hats emblazoned with the slogan "Trump 2028" on a desk in the Oval Office.

A popular theory among his supporters is that Vice President JD Vance could run for president in 2028 on a ticket with Trump.

Trump ruled that idea out this week, and said on Wednesday it was "pretty clear" he couldn't run again. "But we have a lot of great people," he said.

No way to 'amend Constitution'

House Speaker Mike Johnson told a news conference at the Capitol on Tuesday that he spoke with Trump about seeking a third term but doesn't "see the path for that."

"It's been a great run, but I think the president knows, and he and I've talked about, the constrictions of the Constitution," Johnson said.

"There is the 22nd Amendment," Johnson added, saying that the Constitution is clear even though Trump enjoys taunting Democrats with slogans and hats emblazoned with "Trump 2028".

"I don't see a way to amend the Constitution because it takes about 10 years," Johnson said.

'Going to get a third term'

"You'd need two-thirds of Congress and three-fourths of the states to ratify (it)."

Talk of a third term came after Steve Bannon, Trump's former adviser and one of the key ideologues of the Make America Great Again movement, said last week "there is a plan" to keep him in the White House.

"He is going to get a third term... Trump is going to be president in '28. And people just ought to get accommodated with that," Bannon told an American news outlet.

Asked about the 22nd Amendment, which mandates term limits, Bannon said: "There's many different alternatives. At the appropriate time, we'll lay out what the plan is." 

This isn't the first time confusion swelled over the US President's return for a third term. In May, Trump openly raised the possibility in a highly political address to US troops in Qatar.