Donald Trump trails Hillary Clinton in three battleground states that are likely to determine the fate of his presidential campaign, according to a new NBC News/Wall Street Journal/Marist poll.

The former secretary of state is polling four points ahead of Trump in Iowa, 41 to 37 percent, and holds a 5-point lead in Ohio, which no Republican presidential nominee has won the White House without.

In Pennsylvania, where Trump has campaigned heavily since the general election began, Clinton leads him 48 to 37 percent. The findings are similar to a Quinnipiac University poll released Tuesday that showed Clinton carrying a 12-point advantage over Trump in the Keystone State.

A majority of voters in all three battleground states continue to hold negative opinions of both major party nominees.

Trump is viewed unfavorably by 64 percent of Iowans, while Clinton holds a 58 percent unfavorable rating. In Pennsylvania, 53 percent of voters view Clinton unfavorably and 63 percent have similar negative feelings toward Trump. And in Ohio, Clinton's favorable rating is 60 percent, while Trump's is 62 percent.

The NBC/WSJ/Marist poll of registered U.S. voters was conducted Aug. 3-7.