Carmona in July received $2,500 from New York Mayor Michael Bloomberg, a prominent Independent politician who has run for office before under both the Democratic and Republican parties. Bloomberg has made only four contributions this cycle, as of the last filing period, including $2,500 to Sen. Orrin HatchOrrin Grant HatchTimeline: Trump and Romney's rocky relationship Key Republicans say Biden can break Washington gridlock Trump awards Medal of Freedom to racing industry icon Roger Penske MORE (R-Utah), who faced a tough battle for the Republican nomination in his state, and Democratic candidate for Florida's 10th district Val Demings, one of the Democrats' top hopes to take a House seat.

He also received $1,000 in August from Van Hipp Jr., the former chairman of the South Carolina Republican Party, who now works for a defense lobbying firm. Hipp has contributed to a number of candidates from both parties this cycle, but has donated funds to Republicans more consistently, including presumptive presidential nominee Mitt Romney and former candidate Newt Gingrich.

"Dr. Carmona is grateful for the broad-based and bipartisan support his candidacy has attracted," said Carmona spokesman Andy BarrAndy Hale BarrOvernight Health Care ā€” Presented by Partnership for America's Health Care Future ā€” Democrats seek to preempt Trump message on health care | E-cigarette executives set for grilling | Dems urge emergency funding for coronavirus Democrats slam GOP on drug prices in bilingual digital ads On the Trail: Forget the pundits, more electoral votes could be in play in 2020 MORE.

Despite that support, however, Carmona has a tough fight ahead for the seat, with two of the last three polls of the Senate race showing Rep. Jeff FlakeJeffrey (Jeff) Lane FlakeMcSally launches 2020 campaign Sinema will vote to convict Trump Senate drama surrounding Trump trial starts to fizzle MORE (R-Ariz.) in the lead ā€” though the last survey, from Democratic-leaning Public Policy Polling, showed them tied.

And Flake's campaign was quick to highlight the support the candidate has received from liberal groups, including a number of prominent Democratic lawmakers.

"As long as Richard Carmona is boasting about out-of-state contributions, Iā€™d point out the thousands in donations he has received from the PACs of several unions, left-wing groups, and liberal leaders like Bernie SandersBernie SandersDemocrats redefine center as theirs collapses Speculation swirls around whether Bloomberg will make Las Vegas debate stage Pelosi: 'I'm not counting Joe Biden out' MORE, Al FrankenAlan (Al) Stuart FrankenAl Franken blasts Susan Collins: She'll let Trump 'get away with anything' Bill Press: Don't forget about Amy Key moments in the 2020 Democratic presidential race so far MORE, and Harry ReidHarry Mason ReidHarry Reid: 'People should not be counting Joe Biden out of the race yet' Warren highlights work with Obama, Harry Reid in new Nevada ad Yes, Democrats have to defend their African-American base against Trump MORE that routinely work against the interests of Arizonans," said Flake spokesman Andrew Wilder.

--This post was published at 4:05 p.m. and updated at 4:53 p.m.