President Donald Trump said Monday that Americans want him to run for another term, a step banned by the US constitution but which he continues describing as possible.

"People are asking me to run," Trump told reporters in the Oval Office when asked about the possibility of a third term.

"I don't know. I never looked into it. They do say there's a way you can do it, but I don't know about that, but I have not looked into it," Trump said.

Trump was asked about the prospect of a race pitting him against former president Barack Obama, who served two terms.

"That would be a good one, I'd like that," Trump said.

"I'm not joking" about the idea of seeking a third term, Trump said Sunday in an interview with NBC News.

The 78-year-old Republican served from 2017 to 2021 and began his second term in the White House on January 20.

The first US president, George Washington, established a tradition by not seeking a third term after completing his second one in 1797.

But this tradition was not formally added to the US constitution until after World War II, with the ratification of the 22nd amendment in 1951.

It says no one can be elected president more than two times.