Story highlights

The narrow lead is within the poll's 3-point margin of error

Clinton had previously topped Trump in a similar poll in April

Washington CNN —  

Donald Trump holds a slight lead over Hillary Clinton – 45% to 42% – among registered voters, according to a new national Fox News poll.

The lead is within the poll’s 3-point margin of error, but could reflect growing support for the presumptive Republican nominee as the likely Democratic nominee, Clinton, remains mired in a contentious primary fight with rival Bernie Sanders.

Trump’s standing in the poll, released Wednesday, shows an improvement for the billionaire businessman from a Fox national poll in April showing Clinton on top, 48% to 41%.

Still, early national polling has painted a mixed picture – a recent CNN/ORC poll showed Clinton leading Trump by 13 points, 54%-41%.

As has been the case in most polls, Trump and Clinton face a significant gender and racial gap among their supporters.

Donald Trump’s history of controversy with women

Trump has a double-digit lead among men, while Clinton has the edge among women by double-digits, though Trump’s advantage is slightly larger among men than Clinton’s is among women. And while Trump wins white voters – including white women – by more than 20 points, Clinton enjoys even larger margins among African-American and Hispanic voters.

Opinion: Listen to the Trump voters

A majority of voters also have negative opinions of the candidates and say that both Clinton and Trump are dishonest, though Trump fares slightly better on that measure.

The Fox poll finds party unity is about equal – 83% of Democrats say they support Clinton, and 82% of Republicans say they back Trump. Republicans, however, express more enthusiasm about the election, with 74% saying they are extremely or very interested in the election, compared to 66% of Democrats who say the same.

The Fox survey also polled voters on a general election between Trump and Sanders, and found Sanders leads Trump 46% to 42%, but that’s down from his lead in Fox’s April poll, where the Vermont senator led Trump, 52% to 39%.

The Fox News poll surveyed 1,021 registered voters nationwide between May 14-17 and has a margin of error of plus or minus 3%.