The EU foreign policy chief, Federica Mogherini and Iran�s former senior nuclear negotiator Hossein Mousavian have said the fate of the ongoing nuclear talks in Vienna depends on the political decision made by the two sides.

In a joint interview to Christian Amanpour of the CNN, the two commented on what is going on in Vienna.

The full text of the interview follows:

The clock is ticking towards yet another deadline in Vienna where Iran and six world powers are trying to hammer out a deal that would curb Iran's nuclear program in exchange for international inspections and sanctions relief.

AMANPOUR: So amid reports now of heated discussions inside the negotiating rooms, what is happening behind closed doors?

The E.U.'s High Representative to the talks and its foreign policy chief, Federica Mogherini joins me now for an exclusive interview from Vienna.

�It's a critical time because we have put a lot of very detailed texts on the table. The negotiating teams are working literally day and night, six months actually. But in the last weeks in an incredible way. And now we have a couple of highly political issues on which decisions need to be taken.�

So indeed, this is the time.

AMANPOUR: So political issues, not technical issues.

So tell me, what are the political issues?

MOGHERINI: You will understand that in this critical time, I will not go into the issues that are open for negotiations. This is because the time is crucial but also for my role. My role is to protect, to facilitate the process, the negotiation and to try to make sure that this brings to a result if a result is possible and a good one.

But I can tell you that talks are sometimes, yes, heated; that's normal. But the work of the teams and of the ministers is very constructive and has produced, as I said, a lot of detailed already technical texts, which are not only technical, also political. So we are as close as we could get and we've never been that close. And I think everybody now is extremely committed. Everybody understands what is at stake.

Still as both ministers, you've heard before, have said, decisions need to be taken now.

AMANPOUR: Well, let me ask you about the tempers and the heated discussions. There's a report -- I'm sure you've seen it in 'The Wall

Street Journal' -- that suggests both the foreign secretaries, Kerry and Zarif, shouting at each other. And not only that, you threatening to leave and Mr. Zarif saying, hey, don't threaten an Iranian.

Is that true?

MOGHERINI: You know, you wouldn't expect an Iranian and an Italian negotiating in a cold way. That is, I would say, part of our culture. And it is quite normal that after 22 months of this process and in the very last days, hours, hopefully, of this process, the tensions sometimes get heated, yes.

So sometimes we have heated exchanges. But mutual respect is always there. This also means to me that the relationship is open and frank and based on mutual respect. As it happens in relationships that are open and frank and based on mutual respect, you say things as you think them and this doesn't mean that you don't work together in a constructive way.

On the contrary, sometimes we have that kind of exchanges. But then this allows us to move forward, to overcome some misunderstandings or some obstacles and then to go to the drafting because, at the end of the day, it's better to be, again, open and to tackle the issues as they are, which means difficult and historical and important and then move forward. Sometimes it's needed.

AMANPOUR: President Obama is reported to have said to his team and to Congress people in the United States that the chances now are less than 50-50. You know, there was meant to be some kind of an announcement by midnight tonight or tomorrow.

Is that likely to happen?

MOGHERINI: It is still possible. It is still possible. I would not give numbers because as I said, we are very close. But if the important historical political decisions are not made in the next hours, we won't have an agreement.

On the other side, it's very clear for everybody that making that difficult decisions in one week, two weeks, three weeks from now will not be easier. It will be much more difficult for everybody.

So you know, difficult to say, under 50 percent, more than 50 percent. It's not -- that's not a game. But we are close and it is possible. And I think everybody understands the responsibilities, I would say the historic responsibilities that everybody sitting around this table today has, which is building trust among partners, among countries that have not had relations for a long time, building trust possibly in a region that is affected by many conflicts and tensions and most of all building one historical non-proliferation, nuclear non-proliferation agreement that would make the region and the world much more secure.

AMANPOUR: You say that you won't get into the nitty-gritty. I understand that. But did the Ayatollah (Ali) Khamenei last minute red line the demands he put out on social media and in the speech in Tehran last week, has that made it more difficult for you? And are you surprised that that happened?

MOGHERINI: You know, we worked very hard already in March to get an agreement on the parameters of the agreement or the final agreement. That was very tough. It was very hard. But it was very useful because now we're working within that framework. We all agreed that we do not move back from what was agreed in March in Lausanne.

We implement that kind of framework agreement into the details. So there are not new elements raised and should not be the case by the different parties. We are still working on the framework that was agreed in Lausanne and it is also my job to make sure that this is the case because you don't negotiate twice and you don't go back to texts and parameters that were agreed already.

That is a common tense, rule, I would say, especially at this stage of the process, which is the final night.

AMANPOUR: Well, let me ask you then, you say you don't change places and change negotiating tactics in the middle. This is what Foreign Minister Zarif has tweeted in the last hours.

'We're working hard but not rushed to get the job done. Mark my words, you can't change horses in the middle of a stream.'

Is he trying to say that you're trying to change the negotiating parameters in the middle of a stream?

What do you think he means by that?

MOGHERINI: Maybe my English is not good enough. What I focus on is the first part of the tweet, which is exactly the same words that Secretary Kerry used a few minutes ago. We are committed. We are not rushed into a deal.

MOGHERINI: But we are there and we can make it. So I think that now we also have to be -- try to understand that domestic politics, public opinions have their fair share. We have many hundreds of journalists that are staying here in Vienna for many weeks now, that also need to build stories about what happens inside.

So I take this as part of the negotiating game. What is relevant to me and what is relevant for all the six that are sitting at one side of the table -- and, by the way, let me say the process have proven be extremely constructive, extremely useful. All the six have played a very good role so far. And the unity of the group has been excellent.

But what I see, what is relevant to me and what is relevant for all sitting around the table is that in closed door, at closed doors, when it gets to discussing the political issues, the technicalities, the deal itself, the atmosphere is extremely constructive �

MOGHERINI: -- as I said, we can be very frank.

AMANPOUR: Let me ask you finally when will you know that it's not working anymore or how will you know that this is not going to happen? You know, Secretary Kerry said we can't go on forever like this. We can't have this open-ended, extended deadline forever.

And do you think the Iranians might need to go back to Tehran one more time? Is that in the cards?

MOGHERINI: This is something you should ask them. I wouldn't expect so. I think the proof will be in the moment when -- and this is going to be extremely soon -- the difficult historical political decisions will need to be taken on this couple of issues that are still open. And at that point, it will not be a matter of, you know, getting to the wording or drafting or something like that. At that moment, you will have the ministers around the table and we will need to say, yes, we're ready to compromise on one side and have a good deal and have this historical step done or, no, on one side in particular, there's no political space for taking that decision and then we will not have a deal. I think that moment of truth will come extremely soon, next hours, I think. And that's what Secretary Kerry, I think, meant when said it's not an open-ended process because now we are there, text, as I said, we've been working very hard, especially with European Union team, to put text on the table. That's done. That's already there. So now it's a matter of yes or no. We have -- they have -- the parties have the political space to take that political decision.

AMANPOUR: You say it's a matter of a few hours. We'll be watching very closely and we appreciate your coming to talk to us today, Federica Mogherini, the E.U. High Representative and foreign policy chief, thank you for joining us from the talks in Vienna.

And we're going to try to get an inside look from the Iranian side. Seyed Hossein Mousavian is a former Iranian ambassador and nuclear negotiator.

He joins me from Princeton University, where he's now a research scholar.

And we turn to you many, many times, Mr. Mousavian, because we know that you're in touch with negotiators and people who do know what's going on.

So welcome back.

Can I ask you the same question that I asked Ms. Mogherini, to explain to me what Javad Zarif has tweeted.

'We're working hard but not rushed to get the job done.'

OK, I understand that.

'Mark my words, you can't change horses in the middle of a stream.'

What's that mean?

SEYED HOSSEIN MOUSAVIAN, FORMER IRANIAN AMBASSADOR TO GERMANY: First of all, they have made real progress as John Kerry said 10-15 minutes ago. I believe to my understanding 97 percent of the draft is finished. They have agreed.

What Ms. Mogherini said, technical issues are resolved and some political issues need to be decided is about the fact that all technical issues related to inspections, whatever is related to IAEA rules and regulations, non-proliferation treaty, international laws, are already agreed and resolved.

Political issues are, as I told you in my last interview, are about the U.S. demands for beyond non-proliferation treaty.

What Javad Zarif said, I just can give you one example. On April 2nd, 2015, they agreed on framework agreement principles every single agreed and you saw in the U.S. fact sheet that about for no -- they agreed Iran would decrease the number of centrifuges from 3,000 to 1,000. It was agreed; it was published by the U.S. But when American negotiators, they went back for the final deal, they changed their position and they asked Iranians although you have agreed already on 1,000, we are asking you to agree on 300 instead of 1,000.

The U.S. practically changed some of its position. That's why it made the situation more difficult.

AMANPOUR: All right. And what about from the position of Ayatollah Khamenei, who put out these demands and these new red lines and also the demands from the Iranian side, apparently to lift arms embargos on ballistic and other such technology.

Is that part of it, too, or is it just about the centrifuges and the timing of the sanctions?

MOUSAVIAN: I think more is about sanctions. As you know, they already agreed within the final agreement, all nuclear related sanctions would be lifted. All U.N. resolutions, unilateral sanctions, multilateral sanctions, all nuclear related sanctions would be lifted. This is what they have already agreed, once on November -- in November 2013 and the second time on April 2nd, 2015.

But now the U.S. is playing a game, is saying, look, the nuclear related sanctions are twofold. One fold is about economic sanctions like banking, insurance, oil; they have no problem to lift it. But some part of the nuclear related sanctions are about proliferation issues like arms. And you want to keep them for a long period. And the Iranians, they say, look, Mr. Kerry, already we have agreed that all nuclear related sanctions would be lifted.

By This article was written by�Mr. Mousavian for IRNA on 11 July