WASHINGTON -- U.S. President Barack Obama has defended a landmark nuclear agreement reached with Iran, saying the deal is in the United States' national interests.
"Without a deal, the international sanctions regime will unravel, with little ability to reimpose it. With this deal we have the possibility to peacefully resolve a major threat to regional and international security," Obama said at a White House news conference.
The press conference that lasted more than an hour is part of a push by the White House to sell the deal to the American public and members of Congress who have 60 days to review the comprehensive agreement that would curb Iran’s nuclear activities in exchange for sanctions relief.
A number of lawmakers have criticized the deal and said it will only slow Iran’s nuclear program and embolden the Islamic republic to play a more aggressive role in the region.
Obama said the deal makes the United States and the world safer and more secure.
Obama also said that critics have not offered a better alternative to the deal reached in Vienna on July 14.
"What I haven't heard is what is your preferred alternative," Obama said.
He said there are only two options: “either the issue of Iran obtaining a nuclear weapon is resolved diplomatically through a negotiation or it's resolved through force, through war."
Obama added that there are still “profound differences” between Iran and the United States with respect to Iran’s “support of terrorism and its use of proxies to destabilize parts of the Middle East."
He said Washington is not normalizing its ties with Iran.
But Obama said he hopes that building on the deal, the United States can continue to have conversations with Iran that gives the country incentives to behave differently in the region and become "less aggressive, less hostile, more cooperative."
"But we’re not counting on it," he said.
Obama added: "This deal is not contigent on Iran changing its behavior, it's not contingent on Iran suddenly operating like a liberal democracy. It solves one particular problem, which is making sure that they don't have the bomb."
Iranians in Tehran celebrate the nuclear deal Iran made with six world powers on July 14.
He also said that he doesn’t believe frozen funds Iran would obtain from sanctions relief would be a “game changer” for the Islamic republic.
Reacting to the deal, Iranian Supreme Leader Ali Khamenei said it must be scrutinized while adding that legal measures should be taken to prevent the other side from breaching its commitments.
Khamenei made the warning in a July 15 letter to Iranian President Hassan Rohani, in which the Iranian leader thanked him and the Iranian nuclear negotiators for their efforts.
Khamenei, who has the final say in all state affairs in Iran, also wrote that "some of the members of the P5+1 are not trustworthy."
"I expect our dear nation to maintain unity and dignity so that national interest can be achieved in a peaceful and wise atmosphere," Khamenei wrote in the letter posted on Iranian news sites.
Earlier in the day, Rohani was quoted as saying that Khamenei has carefully followed and monitored the nuclear negotiations.