Watch President Barack Obama's full interview this Sunday on CNN's "GPS with Fareed Zakaria" at 10 a.m. EST.

Washington (CNN) President Barack Obama is standing by his comparison between Iranian hardliners and Republicans who he says are dead set on derailing any nuclear deal.

"What I said is absolutely true, factually," Obama told CNN's Fareed Zakaria in an interview that will air in full Sunday.

"The truth of the matter is, inside of Iran, the people most opposed to the deal are the Revolutionary Guard, the Quds Force, hardliners who are implacably opposed to any cooperation with the international community," Obama said.

Senate Majority Leader Mitch McConnell promised that the Senate would debate the Iran deal next month . He also knocked Obama on Thursday for claiming the only option to avoid war with Iran is a deal.

"That's an absurd argument, and it's the one they've made from the very beginning, that it's either what the President negotiates with the Iranians or it's war," McConnell said. "That's never been the alternative."

Read More