Donald Trump at a campaign event in Myrtle Beach, S.C., on Friday. (Jabin Botsford/The Washington Post)

MYRTLE BEACH, S.C. — As Donald Trump pitched himself as "a unifier" during a rally in this beach town Friday afternoon, he criticized President Obama for not doing enough for the African Americans who helped vote him into office.

"You know, Barack Obama, African American. If I were African American, I would be so angry at him," Trump said to a crowd of 5,200. "African American youth has an almost 60 percent unemployment rate. African American people that are 25 — prime-time age — 25 to 40 have such a high unemployment rate, you wouldn't believe."

A woman in the audience shouted "Amen!"

"It's gone up, and it's gotten worse since he's been president," Trump continued. "Now, he's African American. If I were African American, I wouldn't like him very much. I will do more for the African American people than Barack Obama has ever done. I will do more in one year. I will do more for the African American people in one year than Barack Obama has done in his seven years, soon to be eight years — and then, by the way, he's out and thank goodness."

The crowd roared with applause and cheers.

(According to the Bureau of Labor Statistics, the unemployment rate for African American men age 20 and over is 8.4 percent; for African Americans of both sexes age 16 to 19, it's 25.2 percent.)

The South Carolina Republican primary is Saturday, and Trump hopes to win — and win big, cementing his credibility and easing his way to the nomination. More than a quarter of South Carolinians are African American or black, a massive voting bloc that usually participates in the Democratic primary but in recent years has been increasingly courted by Republicans. Trump has pledged that here and nationally he will win the votes of minorities who want him to protect their jobs and boost the economy.

But the crowd at Trump's Friday rally was, as it often is, overwhelmingly white. Ahead of Trump's arrival, the Rev. Mark Burns — an African American pastor based in South Carolina who produces a gospel television show — fired up the crowd with a passionate defense of Trump's immigration positions against criticism from Pope Francis. He then urged the crowd to vote on Saturday.

"We will never, ever, ever allow Bernie Sanders or Hillary Clinton to ever step foot in the White House," Burns said as the crowd booed the two Democratic candidates for president. "Because I know you're going to make sure we elected a man who believes in the name of Jesus Christ."

Following Burns were two sisters from North Carolina who often campaign with Trump: Lynnette “Diamond” Hardaway and Rochelle “Silk” Richardson.

"We are African American women, and Al Sharpton does not speak for us," Hardaway said, referring to the civil rights activist and Baptist minister who has become a television pundit. "And we are voting Donald J. Trump."

Hardaway urged the crowd to "get out and vote" in the Republican primary, even if they are Democrats.

"Are you all on the Trump train?" she asked as the crowd roared with applause. "I don't hear you! Are you on the Trump train?"

The crowd got louder.

"Then get out and vote!" she yelled. "All board! All board! All right! Choo, choo!"