Protesters poured into New York's Times Square on Wednesday to denounce the Iran nuclear deal as a threat to Israel and global security, demanding that Congress reject the pact, AFP reported.
Speakers, including Republican politicians, called on Congress to throw the deal out, whipping up the crowd that included supporters of Jewish and evangelical Christian groups.
"We're here as Americans to speak with one voice to say stop Iran now, reject this deal," said George Pataki, the former three-term Republican governor of New York.
"This is a God-awful deal, this must be rejected. Congress must do its job and stand up for the American people, stand up for our safety and say no to this Iranian deal," he added, according to AFP.
Jeffrey Wiesenfeld, co-organizer of the Stop Iran Rally, said that there were 10,000 people in the crowd. Protesters held up American flags and placards denouncing the deal.
A spokesperson for the organizers said protesters had packed an entire block on both sides of Seventh Avenue.
The rally expressed support for Israeli Prime Minister Binyamin Netanyahu, whose criticism of the deal has strained relations with President Barack Obama.
Recent polls have suggested that of the 79 percent of Americans who heard about the deal, 48 percent disapprove.
Organizers played a montage of news reports about bombings around the world carried out by extremist groups linked to Iran. "Iran has been killing Americans for 36 years," it said.
"Stop the deal."
Scholar and Democrat Alan Dershowitz, a Harvard law professor, appealed to fellow liberals to side with Republican opposition.
"It is a bad deal for Democrats. It is a bad deal for liberals. I am here opposing this deal as a liberal Democrat," he was quoted by AFP as having said.
He called the deal bad for America, bad for world peace and bad for the security of the Middle East.
The Republican-majority Congress has 60 days to review the deal and many have already expressed their objection to the agreement. Among them is House Speaker John Boehner, who vowed earlier on Wednesday to "do everything possible" to stop the deal from being approved by Congress.
"While the president's Iran deal may have been applauded at the United Nations, I think he faces serious skepticism here at home," Boehner asserted.
A Republican Senator in the Senate Foreign Relations Committee made clear last week that American legislators are considering imposing further sanctions on Iran, despite the agreement.
President Barack Obama, however, has threatened recently to "veto any legislation" passed by Congress blocking the deal.
A law signed by Obama in May gives Congress the power to review and potentially reject a nuclear deal with Iran, but in spite of his willingness to allow Congress to debate the agreement, Obama has asserted it would be "irresponsible" to object to the deal.