Nearly one fifth of registered Republicans want Donald Trump to drop out of the race for the White House, according to a Reuters/Ipsos poll.
Some 19 percent think the New York real estate magnate should drop out, 70 percent think he should stay in and 10 percent say they "don't know", according to the August 5-8 poll of 396 registered Republicans.
The poll has a confidence interval of six percentage points.
Among all registered voters, some 44 percent want Trump to drop out. That is based on a survey of 1162 registered voters, with a confidence interval of 3 percentage points.
That is 9 points higher than his support for the presidency in the latest Reuters/Ipsos tracking poll.
The figures underscored deep divisions within the Republican Party over Trump's candidacy.
A number of prominent Republicans have declined to endorse him in the November 8 election against Democratic rival Hillary Clinton, citing his fiery rhetoric and policy proposals such as building a wall along the US-Mexican border and temporarily banning Muslims from entering the country.
Mike Smith, a 74-year-old retiree from Clearwater, Florida, said he supported Trump for much longer than he should have, but now feels the candidate should drop out of the race.
Trump "has not comported himself as a leader," said Smith, adding that he might vote for Clinton over his party's nominee.
"His policies don't seem to be well formed, they don't seem to make any sense," Smith said.
"The support he has from Republicans almost seems obligatory rather than voluntary."
Trump found himself embroiled in yet another controversy on Tuesday after saying at a rally that gun rights activists could act to stop Clinton from nominating liberal US Supreme Court justices - a comment his campaign said was misinterpreted, but that Clinton's campaign called "dangerous."