In his weekly address on Saturday, Obama said without the accord, "we'd risk another war in the most volatile region in the world."

After more than two weeks of marathon talks, Iran and the P5+1 group of countries - the US, Britain, France, Russia, China, and Germany – announced the conclusion of nuclear negotiations in the Austrian capital, Vienna, on Tuesday.

Critics—especially congressional Republicans, a handful of Democrats and the powerful Israel lobby have lambasted the nuclear accord, warning that it will only clear Iran’s path to a nuclear bomb.

Obama said critics will make "a lot of overheated and often dishonest arguments" about the agreement.

"There’s a reason this deal took so long to negotiate," he said. "Because we refused to accept a bad deal. We held out for a deal that met every one of our bottom lines. And we got it."

The White House has launched a sales pitch to Congress, it has 60 days to review the Joint Comprehensive Plan of Action (JCPOA) and vote to either approve or disapprove of it.

The House of Representatives reportedly has the votes to pass a resolution, but in the Senate, Republicans would need support from a half a dozen Democrats in order to guarantee a veto-proof majority.

"I welcome all scrutiny. I fear no questions. As commander-in-chief, I make no apology for keeping this country safe and secure," Obama said.

On Tuesday, Obama warned that he would veto any legislation that seeks to block “the successful implementation of the deal.”

The United States, Israel, and some of their European allies accuse Iran of pursuing a nuclear weapon, an allegation Tehran categorically rejects. Several rounds of sanctions have been imposed on Iran because of its nuclear activities.

"This deal actually pushes Iran further away from a bomb. And there's a permanent prohibition on Iran ever having a nuclear weapon," Obama said in his weekly address.

He asserted that if Iran violates the JCPOA, the sanctions “would snap back into place promptly."