Iran and six world powers determined the outlines of a landmark agreement which would curb Iran's nuclear program and potentially lift economic sanctions.
As Obama gears up to sell US skeptics on the deal, he said he is convinced talks are the best way forward.
"As President and Commander in Chief, I firmly believe that the diplomatic option -- a comprehensive, long-term deal like this -- is by far the best option," Obama said in his weekly address.
Many of Obama's Republican opponents in Congress have been skeptical of a deal with Iran and suggested the US may be giving too much away in its negotiations.
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Echoing comments he made hours after the announcement of the agreement, Obama highlighted the rigorous inspections to which Tehran will be subject.
"If Iran cheats, the world will know it. If we see something suspicious, we will inspect it," he said.
"So this deal is not based on trust, it's based on unprecedented verification."
The outline was a major breakthrough in a 12-year international crisis over Iran's nuclear program, but the final deal has yet to be reached.
Iran's arch-foe Israel, widely assumed to have nuclear weapons of its won, reacted strongly against the deal, with Prime Minister Benjamin Netanyahu saying if the text becomes finalised it would "threaten the very survival of the state of Israel.