Donald Trump. REUTERS/Brian Snyder Real-estate magnate Donald Trump suggested on Saturday that he was partially responsible for the US prisoner swap with Iran that was announced earlier in the day.

"I have been going wild for years about the prisoners. I call them the 'hostages.' Our four people," Trump recalled as he spoke at the South Carolina Tea Party Coalition Convention.

"So I've been hitting them hard," he added. "And I think I might have had something to do with it, if you want to know the truth. Who's using it? It's a part of my staple thing. I mean, I go crazy when I hear about this. You go absolutely wild."

Trump has been blasting President Barack Obama's administration on the campaign trail for not securing the release of the four Americans, including Washington Post correspondent Jason Rezaian, before agreeing to its nuclear deal with Iran.

"How is it possible?" Trump asked conservatives on Saturday in Myrtle Beach, South Carolina. "We have one who's in there who's a reporter for The Washington Post. He didn't do anything wrong, by the way. Although a lot of the people that work for The Washington Post do. But we won't say that. No, The Washington Post, actually, they've been pretty nice lately."

The Republican presidential front-runner added: "And you have people that didn't deserve to be there."

In contrast, Trump noted, the US was releasing Iranians convicted of "real" crimes. The State Department said it was granting clemency to seven Iranians who had been convicted of crimes or were awaiting trial in the US, according to The Post.

"The United States also removed any Interpol red notices and dismissed any charges against 14 Iranians for whom it was assessed that extradition requests were unlikely to be successful," the State Department reportedly said.

Trump said the prisoner swap was a bad deal for the US and emphasized the $150 million in sanctions relief that he says the US is releasing to Iran as part of the deal to curb Tehran's nuclear ambitions. According to PolitiFact, Trump is exaggerating that total somewhat.

"They're getting seven people that they've wanted," Trump said of Iran. "Much more serious. Real people — 'real people' meaning they've committed real problems. And they're getting I guess 14 or 15 other people that are on the watch list of terror. These are really bad dudes. ... They're getting essentially 22 people and $150 billion."

He added: "And we're getting back four people that didn't do anything wrong. That's the way we negotiate. That's the way we negotiate. It's so sad. It's so sad."