MILWAUKEE - US Republican presidential candidates on Tuesday roundly condemned President Barack Obama's nuclear deal with Iran, with Florida Senator Marco Rubio suggesting he would re-introduce sanctions if elected to the White House next year.
The agreement reached between Iran and six major world powers will now be debated in the US Congress, but Obama said on Tuesday he would veto any measure to block it.
"It will then be left to the next president to return us to a position of American strength and re-impose sanctions on this despicable regime until it is truly willing to abandon its nuclear ambitions and is no longer a threat to international security," said Rubio, a member of the Senate Foreign Relations Committee.
Rubio urged the Republican-led Congress to reject the deal, but Obama would likely be able to use his veto, which can only be overridden by two-thirds of lawmakers in both houses.
Under the accord, sanctions imposed by the United States, European Union and United Nations will be lifted in return for Iran agreeing to long-term curbs on a nuclear programme that the West and Israel have suspected is aimed at creating a nuclear bomb.
"Based on what we know thus far, I believe that this deal undermines our national security," Rubio said.
Other Republican hopefuls for the November, 2016 presidential election lined up to denounce the accord.
"Undoing the damage caused by this deal won't be easy," said Wisconsin Governor Scott Walker, who announced his presidential bid on Monday at an event in Wisconsin attended by an American once held hostage by Iran.
"But when the United States leads, and has a president who isn't eager to embrace Iran, the world will follow. In order to ensure the safety of America and our allies, the next president must restore bipartisan and international opposition to Iran's nuclear programme while standing with our allies to roll back Iran's destructive influence across the Middle East."
Former Arkansas Governor Mike Huckabee, a conservative, vowed to back Israel, and did not rule out using force against Tehran.
"As president, I will stand with Israel and keep all options on the table, including military force, to topple the terrorist Iranian regime," he said on Twitter.
Lindsey Graham, a senator from South Carolina, called it a terrible deal that would make matters worse. Former Pennsylvania senator Rick Santorum, another candidate, said the administration had capitulated to Iran.