WASHINGTON – Joe Biden's controversial remarks about race this past week risk alienating young Black voters who despise President Donald Trump but are not inspired by his Democratic rival.

When pressed by Errol Barnett of CBS News on whether he'd taken a cognitive test, Biden responded that the question was akin to asking the Black reporter if he would take a drug test to see if "you're taking cocaine or not? … Are you a junkie?"

In a later interview with NPR's Lulu Garcia-Navarro, Biden seemed to draw distinctions between Black and Hispanic populations in the U.S. "Unlike the African American community, with notable exceptions, the Latino community is an incredibly diverse community with incredibly different attitudes about different things," he told the Latina reporter.

He later walked back the comment.

Black voters as a whole delivered the Democratic nomination to Biden, powering his commanding win in the South Carolina primary, which rescued his floundering campaign. But that success was heavily dependent on older Black voters. In a general election, young Black activists and elected officials say last week's comments could make it harder to get their vote.

"Trump is terrible, and he's a racist, and we have to get racists out of the White House. But then Biden keeps saying racist things," said Mariah Parker, a 28-year-old county commissioner in Athens, Ga. "It doesn't make me feel much better that we actually will have an improvement for the Black community with one president over the other."

AP VoteCast data illustrates the generational divide Biden is confronting.

Across 17 states where AP VoteCast surveyed Democratic voters during the primary, Vermont Sen. Bernie Sanders won 60% of voters under 30 overall, to Biden's 19%. And while Biden was strongly supported by African American voters overall, Black voters under age 30 were slightly more likely to support Sanders than Biden, 44% to 38%.

A Washington Post-Ipsos poll conducted in June suggested that while Biden had majority support among Black voters aged 18-39, there was skepticism about Biden himself. Among Black Americans under age 40 who were polled, 32% said they didn't feel he was sympathetic to the problems of Black people. And 24% of respondents under 40 said they felt Biden is "biased" against Black people, in contrast to much lower percentages for middle-aged and senior respondents.

Part of the challenge for Biden, said activist Kristin Fulwylie Thomas, is the perception among young Black voters that he's too moderate to deliver on issues that are important to them. The 31-year-old managing director of Equal Ground, an Orlando-based group working to boost turnout among Black voters across Florida, said she hears this concern from people in her community and voters across the state.

"What I'm seeing and what I'm hearing among young Black voters is that Biden was not their first choice, so folks are not excited to vote for him this November," she said.

Every gaffe makes it harder for Biden to generate that excitement.

Michigan state Rep. Jewell Jones, who at 21 was the youngest elected official ever in Michigan, said that he's seen a number of Biden's comments on Black voters, along with his past support for the 1994 Crime Bill that contributed to mass incarceration of Black Americans, pop up on social media and raise questions among his peers.

"Young people are really holding people accountable these days," he said. "Anything that comes up that they think is questionable, they'll challenge."

Jones, now 25, said the issue with young Black voters is "not necessarily skepticism about whether or not he's able to do the job."

"Young people today want to know, are politicians' hearts in the right place?" he said.

The Biden campaign says it's working hard to reach out to young Black voters, and points to events hosted by its young voter outreach coalition, as well as outreach geared specifically toward Historically Black Colleges and Universities and Black sororities, among an array of other events broadly geared toward Blacks nationwide.

Birmingham, Ala., Mayor Randall Woodfin, who supports Biden, swept aside Biden's comments last week. He noted that Biden, unlike Trump, later clarified his comments.

"I truly believe that he wants to do the right thing moving forward," he said.