President Barack Obama speaks during a joint news conference with Ethiopian Prime Minister Hailemariam Desalegn, Monday, July 27, 2015, at the National Palace in Addis Ababa. Obama is the first sitting U.S. president to visit Ethiopia. (AP Photo/Evan Vucci)

(CNSNews.com) - Sen. Ted Cruz (R-Texas), a critic of President Obama's Iran nuclear deal, is inviting President Obama to debate him on that topic:



"I'll make an invitation right here tonight," Cruz told Fox News's Sean Hannity on Monday. "I will invite President Obama at any time and place of his choosing to debate the substance of the Iran deal. Let's do it in front of the American people anytime in the next 60 days that Congress has to review this deal.



"If he's so convinced he's right on the substance, I will welcome him anytime. And if he's unwilling to show up, he can send as a proxy John Kerry. Let's debate the substance of how much this endangers the United States of America, Israel and the world. It's the single greatest national security threat facing America."

Cruz issued the invitation after President Obama, speaking in Ethiopia on Monday, criticized Cruz and other Republicans for the way they have stated their opposition to the nuclear deal with Iran.



"We've had a sitting senator who also happens to be running for president suggest that I'm the leading state sponsor of terrorism," Obama said in reference to Cruz.



Here's what Cruz actually said earlier this month:



"This deal ensures that Iran, either number one, will acquire nuclear weapons; or number two, will necessitate military action from the United States or Israel. In addition to that, if this deal goes through, and I hope that Congress steps up and stops it, billions of dollars will flow from the United States of America to Iran, the leading state sponsor of terrorism in the world. That money will be spent by jihadist terrorists to murder Americans, to murder Israelis, to murder Europeans. If this deal goes through, the Obama administration will become the leading financier of terrorism against America in the world. I’ve heard this referred to before as the 'jihadist stimulus bill.'"



On Monday, Cruz noted that Obama had attacked Cruz himself but not the substance of Cruz's criticism.



"It speaks volumes that he's halfway across the globe and he feels the need to attack me directly," Cruz told Hannity.



"And it's interesting, Sean, he didn't actually dispute the substantive criticism. So the point that he responds to there is I've pointed out that under the Obama nuclear deal, over $100 billion will flow to Iran. Iran is the world's leading state sponsor of terrorism, so much of that money will end up in the hands of Hamas and Hezbollah and the Houthis and other radical Islamic terrorists. And if this deal goes through, the Obama administration will become quite literally the world's leading financier of radical Islamic terrorism.



"Now, President Obama didn't dispute that. He didn't point to any other entity on earth that would send more money to radical Islamic terrorism. He didn't dispute that billions of dollars in the control of the American government will be used to fund jihadists who will take that money and murder Americans, murder Israelis, murder Europeans. Instead, he simply attacked us."



President Obama said the opposition to his Iran deal is all "rhetoric," not based on facts.



He insisted on Monday that "the overwhelming majority of nuclear scientists and non-proliferation experts think it's a good deal. It's because it's a good deal. It accomplishes our goal, which is making sure Iran does not have a nuclear weapon. In fact, it accomplishes that goal better than any alternative that has been suggested.



"And you've heard me, Darlene, stand up in front of the press corps and try to get a good argument on the other side, that's based in fact as opposed to rhetoric. And I haven't gotten one yet.



"So if you're asking me how do you think our argument's going, it's going great. Now if you're asking me about the politics of Washington and the rhetoric that has taken -- that takes place there, that doesn't always go great."



Obama singled out the comments of Mike Huckabee as "part of just a general pattern that we've seen, that is -- would be considered ridiculous if it weren't so sad."