Risk of war in Middle East without Iran nuclear deal: Obama

US President Obama has been trying to reason with the Republican-controlled Congress to approve the nuclear deal

A risk of war in the Middle East looms large in the absence of an Iranian nuclear deal which was achieved last week, US President Barack Obama has said as he exhorted the Republican-controlled Congress to approve it.

"With this deal, we have a chance to resolve the challenge of Iran trying to get a nuclear weapon peacefully. Without it, we risk yet another conflict in the Middle East," Obama said in his address to the Veterans of Foreign Affairs in Pittsburgh.

"In the debate over this deal, we're hearing the echoes of some of the same policies and mindset that failed us in the past. Some of the same politicians and pundits that are so quick to reject the possibility of a diplomatic solution to Iran's nuclear programme are the same folks who were so quick to go to war in Iraq and said it would take a few months.

"We know the consequences of that choice, and what it cost us in blood and treasure. So I believe there's a smarter, more responsible way to protect our national security. And that is what we are doing," he argued.

"Instead of dismissing the rest of the world and going it alone, we've done the hard and patient work of uniting the international community to meet a common threat.

"Instead of chest-beating that rejects even the idea of talking to our adversaries, which sometimes sounds good in sound bites but accomplishes nothing, we're seeing that strong and principled diplomacy can give hope of actually resolving a problem peacefully," Obama said.

Later in New York, appearing on the popular Daily Show, Obama mocked those who he said seem to believe that if "you had brought Dick Cheney to the negotiations, everything would be fine".

Yesterday, the White House launched @TheIranDeal, a Twitter handle designed to engage the public and correct misconceptions about the deal.

"It will distribute facts, engage online audiences, and be used as a forum by those involved in negotiating the agreement," White House Press Secretary Josh Earnest said.