WILMINGTON, Del. — Presumptive Democratic presidential nominee Joe Biden vowed to address institutional racism in his first 100 days in office as he sought to elevate his voice Monday in the exploding national debate over racism and police brutality.

The former vice president offered emotional support and promised bold action during an in-person discussion with black leaders in Delaware and a subsequent virtual meeting with big-city mayors who are grappling with racial tensions and frustrated by a lack of federal support.

“Hate just hides. It doesn’t go away, and when you have somebody in power who breathes oxygen into the hate under the rocks, it comes out from under the rocks,” Biden told over a dozen African American leaders gathered at a church in downtown Wilmington.

Without offering specifics, he promised to “deal with institutional racism” and set up a police oversight body in his first 100 days in office, if elected. Biden also said he’d be releasing an economic plan focused on education, housing and “access to capital” and investments, especially for minority Americans, later this month.

“I really do believe that the blinders have been taken off. I think this tidal wave is moving,” Biden told the mayors of Atlanta, Chicago, Los Angeles and St. Paul, Minnesota. “I realize we’ve got to do something big, we can do it, and everyone will benefit from it.”

It’s time for us to take a hard look at uncomfortable truths.

It’s time for us to face the deep, open wound we have in this nation.

We need justice for George Floyd.

— Joe Biden (@JoeBiden) May 29, 2020

Biden has struggled in recent weeks to be heard from his makeshift home TV studio over the noise of dueling national crises. But after another night of violent protests, he ventured out into public for the second time in two days and just the third time since the pandemic arrived in mid-March.

His hopeful and collaborative approach marked a contrast to that of President Donald Trump. The Republican president slammed governors as “weak” during a video teleconference on Monday and demanded tougher crackdowns on protesters. Trump also lashed out at Biden on Twitter, writing that “Sleepy Joe Biden’s people are so Radical Left that they are working to get the Anarchists out of jail, and probably more.”

Biden’s softer style may foreshadow how he presents himself in the five months before the presidential election, emphasizing calm and competence as a contrast to a mercurial president. The approach carries the risk of being drowned out by Trump’s much louder voice.

“He’s not in office, and he certainly does not have the megaphone like the person currently occupying the White House does, but I do think our people are looking for someone who can make them feel better during these extremely tough times,” said Rep. Val Demings of Florida, whom Biden is considering as a running mate. “America just needs to be reassured that there’s someone who’s understanding, someone who’s willing to say, ‘Yes, we do have some issues,’ and someone who’s willing to address it.”

Biden delivered an address on Friday calling on white people to shoulder the responsibility of ending America’s systemic racism. But he was largely out of sight over the weekend, which marked the fifth anniversary of his son Beau Biden’s death from brain cancer.

The former vice president’s campaign posted pictures of him visiting a protest site in the city on Sunday afternoon. Earlier that day, he wrote a post on Medium expressing empathy for those despairing about the police killing of George Floyd.

In the early moments of Monday’s gathering at the Bethel African Methodist Episcopal church in Wilmington, Biden listened quietly and took notes. All the attendees, including Biden, wore face masks but lowered them as they spoke.

“The vice president came to hear from us. This is a homeboy,” Rev. Dr. Silvester Beaman said before everyone bowed their heads in prayer.

Biden’s standing with the black community weighs heavily as he works to deny Trump a second term. African Americans rescued Biden’s flailing primary campaign, but it’s unclear if they will turn out for him in large numbers in November.

“I want to make something clear. I don’t expect anything from the black community,” Biden said Monday, insisting he has never taken its support for granted. The former vice president has been doing cleanup since telling a prominent black radio host a week and a half ago that African Americans who back Trump “ain’t black.”

Yet the mayors who spoke with Biden, three of whom are black, were clearly frustrated and angry with Trump, who has offered military support to address violent protests while denying them federal support to address the coronavirus fallout and repeatedly attacking them on social media.

“To see the president of the United States say that he’s going to send the military into our communities but hadn’t mentioned sending a single dime of support into our communities speaks to where we are in America,” said Atlanta Mayor Keisha Lance Bottoms.

Much of Biden’s campaign strategy centers on trying to draw a contrast with Trump on temperament and values. He has called the White House contest a battle for the soul of the nation and has been particularly forceful in condemning Trump’s handling of moments of racial tension.

Gallery • 11 Photos

ANDREW HARNIK/Associated Press

Democratic presidential candidate, former Vice President Joe Biden speaks to members of the clergy and community leaders at Bethel AME Church in Wilmington, Del., June 1.