President Trump's support among some of his traditionally strongest backers - Republicans, white voters and men - is falling, according to a new poll.

A Quinnipiac University poll conducted March 16-21 showed Trump with an approval rating of 37 percent compared to a disapproval rating of 56 percent. The president's approval rating is his worst score ever for a Quinnipiac survey, pollsters said.

The president's approval rating among men is at 43 percent, a drop of 6 percentage points from a survey conducted earlier this month. Among Republicans, Trump's approval rating is at 81 percent, down 10 points from two weeks ago. Among white voters, 50 percent disapprove of the job the president is doing compared to 44 percent who approve. Earlier this month, white voters approved of the job the president was doing by a margin of 49 to 45 percent.

The numbers are likely alarming for the Trump administration, according to Tim Malloy, assistant director of the Quinnipiac University Poll.

"Although taking a beating, he keeps on tweeting to the point where even his fiercely loyal base appears to be eroding," Malloy said. "Most alarming for President Donald Trump, the demographic underpinnings of his support, Republicans, white voters, especially men and those without a college degree, are starting to have doubts."

Trump's disapproval ratings remain high among women (60 percent); Democrats (90 percent); independents (60 percent); and non-white voters (75 percent).

On individual character traits, 60 percent of those polled said the president is not honest, an increase of 5 percentage points from earlier this month. Sixty-six percent said he is not level-headed and 61 percent said he does not share their values.

A total of 73 percent of American voters say President Trump and his Administration make statements without evidence to support them "very often" or "somewhat often." Only 25 percent of American voters say Trump is more honest than most of the previous presidents; 48 percent say he is less honest and 24 percent say he is about as honest.

The Quinnipiac poll included responses from 1,056 voters nationwide. The margin of error was 3 percentage points.