Obama says that today, "because America negotiated from a position of strength and principle, we have stopped the spread of nuclear weapons" in the region.
He said the accord "meets every single one of the bottom lines" of the framework deal.
"Every path to a nuclear weapon is cut off," he said.
US President Barack Obama, speaking live, says the deal demonstrates that "American diplomacy can bring about real and meaningful change."
Both said they realize that the agreement will be the subject of intense scrutiny and that the full text will be available for the world to see later today.
Iranian Foreign Minister Mohammad Javad Zarif, at the same press conference, is repeating some of the same themes that Mogherini touched on. He also called it not just an agreement, but a good agreement.
Mogherini calls it a balanced document that represents the interests of all sides. She says it is not only a deal but a good deal.
France: U.N. resolution to endorse Iran deal to be done quickly
WASHINGTON, July 14 (Reuters) -- France's foreign minister said a nuclear agreement between Iran and major powers will be endorsed by the U.N. Security Council in a matter of days.
"It will be done very quickly," Laurent Fabius told reporters.
Fabius said the five members permanent members of the U.N. Security Council -- Britain, China, France, Russia and the United States -- had co-signed a letter on Tuesday to refer pass the deal to the Security Council for a vote.
Mogherini is speaking as Iran and representatives of world powers are formally announcing the nuclear accord.
Mogherini: We were always aware we had a responsibility to our generation and future ones.
Mogherini: Today is an historic day. It is a great honor for us to announce that we have reached an agreement on the Iranian nuclear isue. With courage, political will, mutual respect, and leadership, we have delivered what the world was hoping for."
Russia's President Vladimir Putin on Tuesday hailed the historic deal reached on Iran's nuclear drive as a "firm choice for stability and cooperation."
"We are certain that today the world has breathed a huge sigh of relief," Putin said in a statement issued by the Kremlin.
"Despite attempts to justify scenarios based on force, the negotiators have made a firm choice in favour of stability and cooperation."
Putin added that the deal will help Russian-Iranian civilian nuclear cooperation and will contribute to combating terrorism in the Middle East. (AP/Reuters)