Donald Trump has insisted he is the "least racist person anywhere in the world."

Slightly more than half of US voters believe President Donald Trump is racist, according to a poll published on Tuesday.

Fifty-one percent of those surveyed in the Quinnipiac University poll said Trump is racist while 45 percent said he is not.

Forty-six percent of white voters polled said the president is racist while 50 percent said he is not.

Eighty percent of black voters said Trump is racist while 11 percent said he is not.

As for Hispanic voters, 55 percent said he is racist while 44 percent said he is not.

Women were more likely than men to believe Trump is racist.

Fifty-five percent of men said he is not racist while 41 percent said he is.

As for women, 59 percent said he is racist while 36 percent said he is not.

Most of the voters polled -- 61 percent -- said Congress should not start impeachment proceedings against Trump. Twenty-nine percent said it should.

The Quinnipiac poll of 1,306 voters nationwide was conducted between July 25 and 28. It has a margin of error of plus or minus 3.4 percentage points.

Trump has been accused of racism for promoting the "birther" lie that Barack Obama was not born in the United States and his tenure in the White House has been marked by tirades against immigrants and prominent non-white politicians.

The president insisted to reporters at the White House on Tuesday that he is the "least racist person anywhere in the world."