Republican Donald Trump on Tuesday night called Democrats the "party of slavery" and praised what he called the millions of black Americans with successful careers as he tries to reach out to minority voters.

Trump has made much-maligned efforts to appeal to black and Hispanic voters, groups that generally support Democrats and are expected to vote heavily for Hillary Clinton in the Nov. 8 election.

"The Republican Party is the party of Abraham Lincoln," Trump said at a rally in Everett, Washington.

"It is the Democratic Party that is the party of slavery, the party of Jim Crow and the party of opposition," he said, referring to racial segregation laws that once existed in the South.

The Republican nominee has said Democrats have failed minority voters with economic policies that have not improved their job prospects, but his attempts have been criticized for painting a bleak view of all blacks and Hispanics.

Clinton last week released an ad mocking Trump's attempts to reach those groups and showing headlines about a racial discrimination lawsuit the New York real estate mogul faced in the 1970s.

A prominent supporter of Trump's apologized on Tuesday for sending out a tweet that showed a cartoon image of Clinton in blackface.

Trump sought to correct course in Washington state on Tuesday, saying millions of blacks "have succeeded greatly" in art, science, sports and other endeavors.

"But we must also talk about those who have been left behind, the millions suffering in disastrous conditions in so many of our inner cities," he said.