Mayor Bill de Blasio officially entered the 2020 race for president Thursday morning, vowing to make his campaign a battle against corporations and the wealthy — especially fellow New Yorker Donald Trump.

In an announcement video, de Blasio touted his familiarity with the president: "I know how to take him on."

"Donald Trump must be stopped," he added.

Trump did not waste much time in ripping de Blasio's candidacy. "He is a JOKE," the president tweeted Thursday morning.

TRUMP TWEET

After the announcement, de Blasio travels to Iowa and South Carolina for multiple stops over the course of four days, NBC News reported Wednesday.

De Blasio, 58, has faced more resistance to his presidential aspirations — including from his own constituents — than nearly any other Democrat in the race.

Recent polls from Quinnipiac University show the mayor's approval rating underwater in New York City, and 76% of New Yorkers told the pollster in April that de Blasio should not run for president. De Blasio's staunchly progressive rhetoric appears to have turned off New York Republicans: 70% of them disapproved of their mayor, according to Quinnipiac's April poll.

He is not particularly popular in early surveys of Iowa and New Hampshire either.

Nevertheless, de Blasio took a number of steps signaling his intention to run for the White House. The New York Times reported that de Blasio traveled to battleground states, held pricey donor events and spoke at high-profile political conferences.