Bill de Blasio, the mayor of New York, has become the latest Democrat in the US to launch a 2020 presidential bid.
He joins a crowded field of around two dozen other candidates.
Mr de Blasio made his announcement in a video released this morning.
He explained: "As President, I will take on the wealthy, I will take on the big corporations - I will not rest until this government serves working people.
"Donald Trump must be stopped - I've beaten him before, and I will do it again."
Mr de Blasio hailed what he called "big, meaningful progressive victories" during his term - and pledged to do the same for the entire US.
The 58-year-old became New York mayor after a landslide victory in 2013, and won a second term in 2017.
One of his signature programmes in office has been introducing a universal 'pre-kindergarten' - or PreK - programme in the city for young, preschool children.
However, the mayor has also faced declining approval ratings over the years - and a recent Quinnipiac University Poll found that more than three quarters of New York voters believe he shouldn't run for president.
With around nine months to go until the start of the primary campaign to choose the Democratic nominee, polls have indicated that former vice president Joe Biden is the early frontrunner in the race.
However, there has also been substantial support for Vermont senator Bernie Sanders, as well as significant backing for candidates such as Elizabeth Warren, Kamala Harris and Pete Buttigieg.
