GREENVILLE, S.C. (AP) — GOP presidential candidates Donald Trump and Ted Cruz are expected to headline a Capitol Hill rally against President Obama's proposed nuclear agreement with Iran, both candidates confirmed Thursday.

Trump, the Republican front-runner by far, announced the event during a 45-minute speech in South Carolina. Cruz aides said the Texas senator extended the invitation to the billionaire developer ahead of Congress' vote on the accord in mid-September.

Cruz's campaign statement said the event is sponsored by Tea Party Patriots, the Center for Security Policy and the Zionist Organization of America. The Cruz campaign did not immediately offer other details, including the event date.

Their opposition to the Iran nuclear deal is not the only thing Trump and Cruz have in common. They both appeal to populists angry about the way Washington works and have made immigration one of the top issues of their campaigns. Cruz has refused to join other Republicans in criticizing Trump over the billionaire developer's comments that Mexicans in the U.S. illegally are "rapists" and criminals. Trump has called Cruz "a nice guy."

But they differ in key ways. Trump has nearly universal name recognition and a blunt-spoken campaign style that reflects his background as a reality show star. Cruz's megaphone, even as a U.S. senator from Texas, can't match Trump's. But the Harvard-trained lawyer and former Supreme Court clerk offers polish and a record on immigration policy that's based in his personal background.

Congress is expected to begin debate on the Iran accord when lawmakers return from recess Sept. 8.