“He clearly is very desperate for black support,” said Adrianne Shropshire, executive director of BlackPAC, a progressive group. “This is not something we’ve ever seen before, in terms of opening offices in black communities. There is a reality that we know that some black voters are going to vote for Trump.”

The outreach is not guaranteed to help the president. Ms. Shropshire said that a recent internal poll conducted by her organization showed that about one-third of respondents had been contacted in some way by the Trump campaign. But, she said, “the majority of folks in our survey said the contact made them less likely to vote for Trump.”

Part of the disconnect, she said, was that the message about a surging economy and low unemployment rate was at odds with many people’s lived experience of holding multiple jobs but still struggling to be financially stable.

And then there’s the elephant in the room when it comes to Mr. Trump and black support. “A number of our polls and other national polls show that black voters simply think he’s a racist,” Ms. Shropshire said. “You can show up, but most people believe you’re a racist and that you fundamentally don’t have the interests of black people at heart.”

Brad Parscale, Mr. Trump’s campaign manager, however, said all of the outreach has already increased support.

“At a minimum, we’re double where we were in 2016,” he said on Wednesday.

Later, the Republican National Committee said it was funding the outreach centers, which officials said would help Republicans up and down the ballot. Senior campaign officials said they were also considering opening Latinos for Trump offices down the line.