Poll: Clinton leads in Florida, Illinois and Ohio
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Democratic presidential candidate Hillary ClintonHillary Diane Rodham ClintonComey: Trump's 'Spygate' claims are made up Clapper: Trump distorting my comments is Orwellian Mueller probing Roger Stone's finances: report MORE holds leads in Florida, Illinois and Ohio, according to a NBC News/Wall Street Journal/Marist poll released Sunday.

Clinton holds a narrow lead over rival Sen. Bernie SandersBernard (Bernie) SandersTrump: ‘Clapper has now admitted there was spying on my campaign’ Overnight Defense: Trump decision on Korea summit coming 'next week' | China disinvited from major naval exercise | Senate sends VA reform bill to Trump Senate sends major VA reform bill to Trump's desk MORE (I-Vt.) in Illinois, 51 to 45 percent.

In Florida, meanwhile, Clinton holds a much larger lead, 61 to 34 percent.

Clinton also holds a large lead in Ohio, taking 58 percent of the vote, compared to Sanders, who takes just 38 percent.

According to the poll, Clinton holds the lead among African-American Democratic voters in all three states. Among Hispanics, she has a slight lead over Sanders in Florida, 51 to 46 percent, but Sanders takes the lead among Hispanics in Illinois, 64 to 30 percent.

In a general election match-up in Florida and Ohio, Clinton and Sanders both lead Republican presidential front-runner Donald TrumpDonald John TrumpGOP nearing end game on immigration votes Tech companies scramble as sweeping data rules take effect Comey: Trump's 'Spygate' claims are made up MORE.

Pollsters surveyed likely Democratic primary voters between March 4 and 10.The results have a margin of error of 4.4 percent in Florida, a margin of error of 4.3 percent in Illinois and a margin of error of 4.6 percent in Ohio.

Clinton leads Sanders by 31 points in Florida, according to a RealClearPolitics average of polls that also shows her ahead of Sanders by almost 18 points in Ohio and almost 14 points in Illinois.

--This report was updated at 12:48 p.m.