. . .

PRESIDENT OBAMA: We also discussed the continuing threat posed by Iran's failure to meet its international obligations. On this we are fully united. We are determined to prevent Iran from acquiring a nuclear weapon. We believe there is still time and space to pursue a diplomatic solution, and we're going to keep coordinating closely with our P5-plus-1 partners. At the same time, we're going to keep up the pressure, with the strongest U.S. sanctions to date and the European Union preparing to impose an embargo on Iranian oil. Tehran must understand that it cannot escape or evade the choice before it -- meet your international obligations or face the consequences.

. . .

ALISTER BULL: On Iran, do you believe that the six-power talks represent a last chance for the country to diffuse concerns over its nuclear program and avert military action?

And, Prime Minister, on Syria, how are you approaching the Russians to get them on board for a fresh Security Council resolution? And do you believe President Bashar al-Assad ought to be tried as a war crime -- a war criminal?

Thank you.

PRESIDENT OBAMA: As David said, we have applied the toughest sanctions ever on Iran, and we've mobilized the international community with greater unity than we've ever seen. Those sanctions are going to begin to bite even harder this summer. And we're seeing significant effects on the Iranian economy.

So they understand the seriousness with which we take this issue. They understand that there are consequences to them continuing to flout the international community. And I have sent a message very directly to them publicly that they need to seize this opportunity of negotiations with the P5-plus-1 to avert even worse consequences for Iran in the future.

Do I have a guarantee that Iran will walk through this door that we're offering them? No. In the past there has been a tendency for Iran in these negotiations with the P5-plus-1 to delay, to stall, to do a lot of talking but not actually move the ball forward.

I think they should understand that because the international community has applied so many sanctions, because we have employed so many of the options that are available to us to persuade Iran to take a different course, that the window for solving this issue diplomatically is shrinking.

And as I said in a speech just a couple of weeks ago, I am determined not simply to contain Iran that is in possession of a nuclear weapon; I am determined to prevent Iran from getting a nuclear weapon -- in part for the reasons that David mentioned. It would trigger a nuclear arms race in the most dangerous part of the world. It would raise nonproliferation issues that would carry significant risks to our national security interests. It would embolden terrorists in the region who might believe that they could act with more impunity if they were operating under the protection of Iran.

And so this is not an issue that is simply in one country's interests or two countries' interests. This is an issue that is important to the entire international community. We will do everything we can to resolve this diplomatically, but ultimately, we've got to have somebody on the other side of the table who's taking this seriously. And I hope that the Iranian regime understands that; that this is their best bet for resolving this in a way that allows Iran to rejoin the community of nations and to prosper and feel secure themselves.