WASHINGTON (AP) — Republican presidential candidate Donald Trump says that if elected he would work to improve the "horrible" international agreement with Iran to rein in that country's nuclear arms program.

"I do like to buy bad contracts," the billionaire real estate mogul said Friday on MSNBC's "Morning Joe" program, explaining why he believes he is qualified to renegotiate the deal, which involved not only representatives of the U.S. but also of Germany, Britain, France, Russia and China.

Trump repeated his charge that the deal was "negotiated by totally incompetent people."

The celebrity businessman's staying power atop polls in the 17-person Republican presidential contest has increasingly put him in conventional candidate situations, including being asked about his approach to foreign policy.

Trump bristled Thursday when well-known conservative radio host Hugh Hewitt asked him about a variety of overseas issues. He accused Hewitt of asking "gotcha questions" when Hewitt quizzed him on the names of top leaders of Islamist terrorism. Trump angrily stumbled through his retort before landing on braggadocio.

"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," he said.

The tense interaction with Hewitt could set up the next GOP debate as a sort of sequel to the first: Hewitt is one of its moderators. At the August debate, Trump rumbled with Fox News host Megyn Kelly, whom he has repeatedly accused of asking unfair questions of him.

At the beginning of Thursday's Hewitt interview, Trump appeared to confuse the Iranian Revolutionary Quds Forces with the Kurds, an ethnic Middle Eastern group. And he also could not explain the difference between Hamas and Hezbollah.

Later Thursday, Hewitt asked another GOP candidate, former technology executive Carly Fiorina, the same kinds of questions, assuring listeners he hadn't shared them with her ahead of time.

"Do you know that difference between Hamas and Hezbollah?" Hewitt asked her.

"Yes. I do," she replied. "And of course, Hamas is focused in Palestinian territories. Hezbollah focuses in Beirut and other places, but the truth is, both of them are proxies of Iran. Both of them threaten Israel."