JUDY WOODRUFF: As pressure builds from critics of a nuclear deal with Iran, negotiators are back in Genevafor another round of talks.Our chief foreign affairs correspondent, Margaret Warner, is also there. I spoketo her a short time ago.

Margaret, hello.So, is there any movement reported today?

MARGARET WARNER: Judy, that's a fascinating question that's hard to answer.

There was a flurry of activity. Undersecretary Wendy Sherman, the whole U.S. delegation flew overnight andjumped right into talks with their European, Russian, and Chinese counterparts, no doubt to avoid the kindof disagreement that sunk it last time.

But, then, when Lady Catherine Ashton, who is the E.U. high representative, and the Iranian foreign minister, Zarif, had lunch today, his deputy foreign minister came out of there saying, we're not talking about substance of any draft right now. We're still talking about progress.

This is the third round of intensive negotiations, and you would think process questions would have been settled quite some time ago. So, it does at least appear as if they have had to reset the starting point tosome degree.

JUDY WOODRUFF: How would you describe the atmosphere? What are people saying outside the meeting, around -- around what's going on there?

MARGARET WARNER: Well, Judy, the feeling was from people here, but also, I think, in respective capitals, that everyone came into this with high expectations, and a kind of a sense that this was the week that they'd clinch this first step on the way to a comprehensive deal.

But, today, there were definitely some sour notes. I mean, Lady Ashton said the lunch was very positive, but there was great attention given to this fiery speech by Supreme Leader Khamenei, in which he said therehad been red lines established that the Iranian delegation could not cross.

And after this lunch, as I said, that Lady Ashton said was positive, the deputy Iran foreign minister said, well, the reason we're not talking substance yet is there is trust that was broken that has to be rebuilt. So the Iranians even late tonight were telling me that there is a sense of mistrust and that we hope wewill get to the -- we will get to the substance tomorrow.

JUDY WOODRUFF: Well, we know the last round of talks didn't end as many had wanted them to in the administration. Has -- how much of a shadow has that cast over what's -- the talks taking place now?

MARGARET WARNER: A huge shadow, Judy.

First of all, clearly, the U.S. and the Iranians and really everyone wants to avoid the embarrassment of last time, when the U.S. and Iran appeared close to the outlines of a deal, and then all the other foreign ministers came in and the French raised sudden objections.

In fact, we had an interesting little tidbit about this today that the U.S. hinted at and the E.U. spokesman confirmed, which was that Lady Ashton had only invited Secretary Kerry last time, and the foreign ministers hearing of this all decided they would come.

The other reason that they want to avoid another setback is that, in the interim, critics any of potentialdeal have really gained ground, especially certainly in Washington. And, right now, Israeli Prime MinisterBenjamin Netanyahu is in Russia lobbying President Putin against the deal.

So, even though U.S. officials say -- said tonight at a briefing, oh, we're not in a rush to get any deal,I do sense from them a feeling of urgency, that if this first-step process goes on too much longer, it could get dragged down by critics at home, especially with new congressional sanctions.

JUDY WOODRUFF: And, Margaret, you mentioned the Iranians speaking about a break in the trust between thetwo countries, and that that trust has to be built back up again. How is the U.S. responding to that?

MARGARET WARNER: Well, we asked this tonight.

And one -- one U.S. official pulled me aside and said, really, that's a negotiating tactic, but the seniorU.S. official briefing us said, when asked about it, it's been tough, and that there are real moments of tension, and this official went on to say, we have critics and skeptics domestically. We all do. And this is a very -- I don't -- don't remember the exact words -- but this is a very difficult thing for us all to do.So, to some degree, I would say they sidestepped the question, but didn't dispute it.

JUDY WOODRUFF: So, given all this, Margaret, how would you describe expectations?

MARGARET WARNER: I think that moment is being prepared for Secretary Kerry and maybe others to fly in.

But, definitely tonight, the tone of briefings from both Iranian and American officials was much more cautious than at this point in the last round. And each one had the tone of someone who doesn't want to get burned again.

JUDY WOODRUFF: Margaret Warner in Geneva, and we will check in with you again tomorrow.

MARGARET WARNER: Look forward to it, Judy.