Interview with British U.N. Ambassador Karen Pierce.
GORANI: Well, with tensions soaring between the U.S. and Iran, Donald Trump says if there is a war, there wouldn't be American boots on the ground and it wouldn't last long. CNN's Fred Pleitgen was the only international journalist to interview Iran's foreign minister a short time ago, in Tehran. He asked about President Trump's warning that an attack on the U.S. would mean obliteration for his country.</s>FREDERIK PLEITGEN, CNN SENIOR INTERNATIONAL CORRESPONDENT: What do you make of President Trump's threats of obliteration, and that war with the United States won't last very long?</s>MOHAMMAD JAVAD ZARIF, FOREIGN MINISTER OF IRAN: Well, he's certainly wrong. But that statement indicates that the United States' intentions are certainly illegal. The United States is not in a position to obliterate Iran. They do not have the capability, other than using prohibited weapons to do this. The Iranian people are prepared to resist any aggression. But we're not seeking war. We don't seek war. We do not seek a confrontation. The actions by the United States over the past few weeks have been confrontational, provocative. Particularly the imposition of sanctions on Iranian leadership, has been an additional insult by the United States against the entire Iranian nation. Iran has been implementing its rights under the nuclear deal. And under Security Council Resolution 2231, the United States is in flagrant violation. And I think President Trump should remember that we don't live in the 18th century. There is a United Nations Charter. And threat of force is illegal under the U.N. (ph)...</s>PLEITGEN: How do we get out of this? How can the world, how can the U.S. walk back from this?</s>JAVAD ZARIF: We did not walk into anything to walk back from it. The United States, trying to undermine the Iranian government, walked into it based on a wrong analysis. I think the B-Team gave President Trump wrong information, wrong analysis. And now, President Trump finds himself in a situation where he believes that he needs to get out.</s>GORANI: All right. Meantime, Iran could be just hours from breaking the nuclear deal that the United States walked away from. Tehran says as early as Thursday, it will speed up the process of enriching low-grade uranium and it will have bigger stockpiles than it's allowed under the terms of that deal. Karen Pierce is the British ambassador to the United Nations and she joins me live from New York. Ambassador, thanks for being with us. What are we -- first, let me ask you for your reaction to Donald Trump tweeting out that if Iran attacks any U.S. asset, that it would mean obliteration for Iran. How do you react to that type of rhetoric from the U.S. president?</s>KAREN PIERCE, BRITISH AMBASSADOR TO U.N.: Well, I think the first thing to say is that it is Iran who shot down an American drone. So there was, in that sense, an attack there. And I believe that's what the president was responding to. But I think the most important thing is that there's de-escalation on all sides. And that we find a diplomatic solution to the current problems and tensions. That's certainly what the United Kingdom is trying to do, along with our partners in the</s>E.U. GORANI: How are you trying to achieve that, a diplomatic solution? Because there's more and more worry in the region that there could be open conflict here.</s>PIERCE: Well, I think this is a very crucial week for Iran, as your introduction implied. We don't want to breach the nuclear deal, the so- called JCPOA. We want it very much to stay within that. We have created some incentives on the economic side, to encourage Iran to stay within the deal. But there's no doubt that there will be consequences if he (ph) breaches the deal, and we will have to think with the rest of the people in the nuclear deal, what those consequences might be. But the most important thing is to keep talking and to try and find a way to de-escalate. I can't stress enough how vital that is at the moment.</s>GORANI: And what consequences are you -- are Europeans considering here, if Iran does not abide by the rules of the deal, the JCPOA, and starts enriching more than is allowed under that agreement. What types of consequences?</s>PIERCE: Well, there are a number of mechanisms in the deal itself that one could look at. There are various economic measures that one could look at. I don't want to go into too much detail because we wouldn't want to signal in advance, our hypothetical response to what is still, even at this late hour, a hypothetical problem. But we would want to get together and think what the consequences should be in practice.</s>GORANI: So from the Iranian perspective, obviously, they're saying, "Why would we, you know, follow the rules when it's the U.S. that walked away? We were basically" -- I mean, you know, "We were not enriching uranium beyond the point that we'd agreed with Western countries. We were not on a path to a nuclear bomb, and it's America that walked away." How do you respond to that?</s>PIERCE: Well, I think you have to remember that this all started because Iran was making a nuclear weapon. And when the nuclear deal, the JCPOA, was agreed, it really was a landmark achievement. And it remains in place, even though America has left it and we regret that. So we really would urge Iran to stick with it and stay within the deal. As I say, this began with an illegal Iranian campaign to make a nuclear weapon. That's why the deal itself is so important.</s>GORANI: Right. But I mean from their perspective, they are saying, "We were doing everything that we promised we would do. It's America that broke that promise."</s>PIERCE: I don't think that changes the fact that the nuclear deal is very important for regional security, it's important for our own security. it's important for global nonproliferation. And if Iran wants to be a responsible member of the international community, and having agreed to the deal and the fact that the other five countries remain in the deal, we very much encourage her to stay in.</s>GORANI: So it's really -- but time is of the essence here. What are your -- are you optimistic that a diplomatic solution can be found in just a matter of days?</s>PIERCE: I don't want to be optimistic or pessimistic. I think we've just got to put our shoulders to the wheel. We sent a minister to Tehran recently, Dr Andrew Murrison, to talk to the Iranians about staying in the deal, talk to the Iranians about de-escalating. I think these steps become all the more intense, they become all the more pressing. I wouldn't want to characterize it one way or another, but obviously we hope everything can be done to avoid a real practical conflict.</s>GORANI: So -- but you're neither here nor there on whether or not you believe this will be a successful mission with the U.K. sending a representative, trying to calm things down and de-escalate?</s>PIERCE: Well, obviously, we hope for success. And obviously, we work really hard for success. But I don't -- at the moment, I think we take it step by step. We respond to what we see. We continue our efforts with our European partners on de-escalation, and we continue to urge all sides to look for a diplomatic solution. I'm not going to -- as I said, I'm not going to characterize that. But obviously, we believe it can be successful and therefore, that's what we're working hard for.</s>GORANI: So we'll see if some of these incentives that the Europeans are proposing will have an impact. Karen Pierce, the British ambassador to the United Nations, thanks so much for joining us from New York. Very tense times --</s>PIERCE: Thank you.</s>GORANI: -- in that part of the world. Meantime, Mr. Trump has just left for the G20 summit in Japan. Iran will likely overshadow that gathering, but CNN's Nic Robertson tells us the U.S. president and his fellow world leaders will have their hands full with many other crises as well.</s>NIC ROBERTSON, CNN INTERNATIONAL DIPLOMATIC EDITOR (voice-over): In Osaka, President Trump will be busy. His overseas entanglements are troubled, threatening global markets. He'll have meetings with President Xi of China, tariffs and the elusive trade deal on the menu. With President Putin of Russia, topics a mystery. But likely Mideast, missiles and maybe election meddling. And with Turkey's populist president, Erdogan, not so popular now, weaker, a troublesome ally, buying weapons from Russia. Then, there'll be time with Saudi's crown prince, Mohammad bin Salman, MBS, giving Saudis a hand up in their post-Khashoggi murder rehabilitation. Running through all these conversations? Iran. Tensions rising, ships attacked, a U.S. drone shot down, Trump threatening Iran with oblivion, slapping on sanctions but holding back from missile strikes.</s>TRUMP: I decided not to strike. They shot down unmanned -- as you know, an unmanned drone --</s>QUESTION: -- think they take your threat seriously now, Mr. President?</s>TRUMP: I think everybody does.</s>ROBERTSON (voice-over): Not so much, according to Iran's president.</s>HASSAN ROUHANI, PRESIDENT OF IRAN (through translator): The White House is suffering from mental disability.</s>ROBERTSON (voice-over): Trump's Osaka challenge? Prove Rouhani wrong. And when over, G20 leaders. But President Xi buys a lot of Iranian oil. Putin backs Iran in Syria. Erdogan is a quite ally of Iran. But MBS should be easy. He wants Iran contained or crushed.</s>ROBERTSON: Trump won't meet the Iranians. They're not here, not a G20 nation. But host, Japanese Prime Minister Shinzo Abe, will talk a lot about them. He's trying to defuse tensions.</s>ROBERTSON (voice-over): He went to Tehran recently, met the leaders. He buys a lot of oil from them, too. If Trump is to avoid war with Iran, Abe could well fix the formula to make it happen. In the space of two days, there's much else for Trump and this elite club of the world's wealthiest nations to discuss, much of it not to Trump's liking. His America First clashes with their multilateralism. On trade, specifically the reform of the World Trade Organization and sustainable development, meaning climate issues. A farewell to the British P.M. too, her last global shindig before being replaced next month. No one-on-one goodbye scheduled with Trump just yet. And as for Iranian tensions, if the door to diplomacy opens despite Iran's threat to shut it, then that will be a success of sorts. If the door to diplomacy opens despite Iran's threat to shut it and that will be a success of sorts. Trump will leave Japan with North Korean nukes on his mind. He's next stop, Seoul, and keeping the plate spinning on another of his stalling overseas initiative, signing Kim Jong-un up to denuclearization. Nic Robertson, CNN, Osaka, Japan.</s>HALA GORANI, CNN INTERNATIONAL HOST: Still to come, we'll have more on the humanitarian crisis at the American border and that heart wrenching tragic photo of a father and his daughter. As we ask, will this image lead to any meaningful change? We'll be right back.