Obama told reporters at the White House a tentative agreement with Tehran could lead to "a resolution to a problem that has been a challenge for U.S. national security for over a decade now and that is getting Iran to, in a verifiable fashion not purse a nuclear weapon."
"The alternative is possibly us having to engage in some sort of conflict the resolve the problem," he said.
"I'm keeping all options on the table," the president said, but repeated he would prefer to resolve the issue through diplomacy.
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