Democratic presidential hopeful Pete Buttigieg says he will keep up his effort to appeal to black voters, whose support will be vital to winning his party's nomination.

The former mayor said during Tuesday night's debate in Des Moines, Iowa, that "the black voters who know me best are supporting me," referencing local leaders in his hometown of South Bend, Indiana.

Buttigieg has built up support in some of the early states but has struggled in South Carolina, where black voters comprise the majority of the Democratic primary electorate. It's the first state where candidates' mettle with black voters is tested.

Buttigieg pointed Tuesday to his endorsement from U.S. Rep. Anthony Brown of Maryland, who earlier this month became the first member of the Congressional Black Caucus to back Buttigieg's campaign.