Donald Trump, leading in the polls and riding a wave of momentum in the race for the Republican presidential nomination, just hit a speed bump named Hugh Hewitt.

The conservative radio host peppered Trump with a host of foreign policy questions in a Thursday interview that produced some uncomfortable moments for the real estate mogul, who appeared upset at the line of questioning.

At one point, Hewitt asked Trump if he was familiar with "General  Soleimani" and the "Quds Forces." (He referred to Iranian Maj. Gen. Qasem Soleimani, commander of the elite Quds Force of the Revolutionary Guard Corps.) Trump said he was but then appeared to mistake the Quds for the Kurds, a Middle Eastern ethnic group.

"The Kurds, by the way, have been horribly mistreated by us," said Trump.

Hewitt corrected him: "No, not the Kurds, the Quds Forces, the Iranian Revolutionary Guards Quds Forces."

A portion of the video was posted on YouTube:

After that, Trump said he thought Hewitt said "Kurds."

"No, Quds," responded Hewitt.

Later on, Hewitt insisted he didn't believe "in gotcha questions." Trump disagreed.

"Well, that is a gotcha question, though," he said. "I mean, you know, when you’re asking me about who’s running this, this this, that’s not, that is not, I will be so good at the military, your head will spin."

Asked what he would do as president if China were "to either accidentally or intentionally sink a Filipino or Japanese ship," Trump refused to say.

"I wouldn’t want to tell you, because frankly, they have to, you know, somebody wrote a very good story about me recently, and they said there’s a certain unpredictable, and it was actually another businessman, said there’s a certain unpredictability about Trump that’s great, and it’s what made him a lot of money and a lot of success," said Trump. "You don’t want to put, and you don’t want to let people know what you’re going to do with respect to certain things that happen."

Hewitt told Trump that when it comes to terrorism, "I’m looking for the next commander in chief, to know who Hassan Nasrallah is, and Zawahiri, and al-Julani, and al-Baghdadi. Do you know the players without a scorecard, yet, Donald Trump?"

Trump said he did not.

"No, you know, I’ll tell you honestly, I think by the time we get to office, they’ll all be changed," he said. "They’ll be all gone. I knew you were going to ask me things like this, and there’s no reason, because number one, I’ll find, I will hopefully find General Douglas MacArthur in the pack. I will find whoever it is that I’ll find, and we’ll, but they’re all changing, Hugh."

For the record, Hasan Nasrallah is the secretary general of Hezbollah; Ayman al-Zawahiri is the new leader of al-Qaeda after the death of Osama bin Laden; Abu Mohammad al-Julani is the leader of Jabhat al-Nusra, or al-Nusra Front, an al-Qaeda affiliate fighting in Syria; and Abu Bakr al-Baghdadi is the leader of the Islamic State, which controls parts of Syria and Iraq.

Ordinarily, an interview like this would put a candidate at serious risk of falling in the polls. But nothing about Trump's candidacy has been ordinary, so it remains to be seen whether it will hurt him or not.

Republican presidential candidate Donald Trump and the media don't always have the best relationship. (Jhaan Elker/The Washington Post)

In the same episode, Hewitt interviewed the GOP race's other business leader-turned-candidate, Carly Fiorina. He asked her the same questions -- informing her that "there's been social media" coverage of how Trump did.

"Aren’t you familiar with General Soleimani?" Hewitt asked.

"Yes," said Fiorina, who also recognized the name of the Quds Force. "We know that the general of the Quds Force has been a powerful tool of the Iranian regime to sow conflict. We also know that the Quds Forces are responsible for the deaths and woundings of American soldiers. We also that the Quds Forces have been in Syria and a whole bunch of other countries in the Middle East."

Fiorina was more hesitant when Hewitt mentioned Nasrallah, Zawahiri and Julani, as well as Islamic State leader Abu Bakr al-Baghdadi.

"Do you know most of these without a scorecard, Carly Fiorina?" Hewitt asked.

"I have to be very honest with you," said Fiorina, "and say that sometimes I can get confused a bit between the name and group because they sound a bit alike sometimes, so I have to pause and think sometimes. But, I certainly know all those names both of the individual leaders and of the terrorist groups."

The former Hewlett-Packard CEO was on firmer ground when Hewitt asked her to differentiate between Hamas and Hezbollah. "Hamas is focused in Palestinian territories," she said. "Hezbollah focuses in Beirut and other places, but the truth is, both of them are proxies of Iran."

Trump hasn't seen the last of Hewitt. He is slated to ask questions at the second Republican debate later this month.

"At the debate, I may bring up Nasrallah being with Hezbollah, and al-Julani being with al-Nusra, and al-Masri being with Hamas. Do you think if I ask people to talk about those three things, and the differences, that that’s a gotcha question?" asked Hewitt.

"Yes, I do. I totally do. I think it’s ridiculous," Trump responded.

What Donald Trump is doing on the campaign trail

U.S. Republican presidential nominee Donald Trump speaks at a campaign event at Trump Doral golf course in Miami, Florida, U.S. July 27, 2016. REUTERS/Carlo Allegri (Carlo Allegri/Reuters)