Republican presidential candidate Donald Trump speaks at a campaign rally in Florence, S.C., on Feb. 5, 2016. (Sean Rayford/Getty Images)

FLORENCE, S.C. — Republican presidential candidate Donald Trump was critical of President Obama’s visit to a Baltimore mosque during a Friday speech here in Florence, S.C., saying that the president “goes to a mosque and apologizes” as Americans are targeted by terrorists.

“Where did they come from?” Trump asked as he spoke about the November terrorist attacks in Paris and San Bernardino, Calif., referencing the attackers who carried out the killings.

“And then President Obama yesterday goes to a mosque and he apologizes. I mean, what’s going on?” he added as the crowd booed. “And you know, it’s all fine, but we have to find out what’s going on.”

Several Republican presidential candidates questioned the merits of the president’s visit. Trump said Thursday that the president “maybe…feels comfortable there,” carrying faint echoes of the billionaire’s years-long demand that Obama release his birth certificate to prove he was born in the United States, a conspiracy theory that he has been frequently panned for championing. Many of Obama’s detractors have also incorrectly insisted that the president is Muslim; he is Christian.

Trump was first asked about the president's visit Thursday during an interview with Fox News's Greta Van Susteren: "I don't have much thought, I think that we can go to lots of places. Right now, I don't know if he's -- maybe he feels comfortable there," Trump said. "We have a lot of problems in this country, Greta, there are a lot of places he can go, and he chose a mosque. I saw that just a little while ago, and so that's his decision, that's fine."

[Trump and Rubio question President Obama’s visit to a mosque.]

President Obama’s speech — during his first visit to a mosque since taking office — celebrated the contributions of Muslim Americans amid a sharp rise in Islamophobia around the United States. “There are voices who are constantly claiming you have to choose between your identities…. Do not believe them…. You fit in here. Right here. You’re right where you belong. You’re part of America, too,” Obama said Wednesday. “You’re not Muslim or American, you’re Muslim and American. And don’t grow cynical.”

The billionaire showman was typically raucous Friday, just days after facing a surprise upset in Iowa by Sen. Ted Cruz, who took first place in the caucuses. The Trump campaign has sought to play down speculation over the effect that his second-place finish in the Hawkeye State will have on his support in New Hampshire, which votes Tuesday, and beyond.

Though Trump was bullish about his chances to seize victory in the Hawkeye State in the days and weeks before caucus day, he has since downplayed those expectations. Trump has repeatedly reminded reporters and supporters of how far his campaign has come since his widely dismissed presidential announcement last June to his place now as the presumptive GOP front-runner.

Trump has increasingly drawn a contrast between himself and Cruz by presenting himself as a unity candidate, someone who can bring various factions in American politics together. He has been very critical of Cruz for failing to cooperate with his colleagues in the Senate.

“We have something special happening. There’s a movement going on,” Trump told the crowd. “A lot of people laugh when I say it but I mean it — I’m a unifier. I bring people together. We have a president who's a divider. He’s a very divisive person. I am a unifier.”

But with just four days until the New Hampshire primary, Trump has faced repeated criticism for not spending more time in the Granite State meeting with voters in so-called “retail campaign” stops. Trump typically flies in for rallies on his private plane and then returns to his home in New York City in the evenings. The campaign, however, added several retail campaign stops Thursday, expanding his scheduled appearances to five instead of his usual one.

[As rivals focus on New Hampshire, Trump takes a detour to Little Rock.]

The campaign says that meeting with as many voters as possible is a top priority, and the large crowds that Trump draws help accomplish that goal.

Nonetheless, that line of criticism gained steam Friday after weather in the Granite State forced the campaign to cancel a rally — their only publicly scheduled event in New Hampshire with just for days before the election. Trump indirectly mentioned his lower-than-expected voter turnout in Iowa, urging voters here in South Carolina to show up to the polls on Feb. 20.

“Will you please get out? You have to vote! It’s going to be a biggie. You won’t be sorry,” he said.

“I don’t want anything, I don’t want your money, I just want your vote. If you don’t get out and vote, we’ve all wasted a lot of time, energy…and our country is going to hell and we’ve got to stop it,” he said toward the end of his speech.

South Carolina Lt. Gov. Henry McMaster (R), who endorsed Trump several weeks ago and cut a pro-Trump radio ad, introduced Trump at the rally. Trump took the stage as “Revolution” by the Beatles played.