NPR- Iran's Foreign Minister Mohammad Javad Zarif tells NPR that renegotiating the 2015 nuclear deal between his country and six world powers would be opening a "Pandora's box" that risks damaging U.S. credibility in future international talks.

In an interview airing Tuesday on�Morning Edition, Zarif says he hopes that French President Emmanuel Macron and German Chancellor Angela Merkel, during their successive visits to the United States this week, will "impress upon President Trump" that the international community "will be much better served if they were to respect the terms of the deal."

"I think the United States doesn't want to send the message to the world that if you negotiate with the United States, the U.S. is going to come back after you had reached an agreement and tell you 'I don't like these parts of the agreement and I want them re-negotiated,' " Zarif tells�ME�host Steve Inskeep during a conversation recorded Monday evening at the residence of Iran's United Nations ambassador in New York.

In the deal signed nearly three years ago, Iran agreed to curtail its nuclear program in exchange for�lifting billions of dollars in international sanctions. U.S. law requires the president to recertify Iran's compliance with the agreement every 90 days, something that Trump has consistently done since taking office, despite his threats to the contrary. The next certification deadline is May 12.

Zarif says if Washington insists on going back on the deal, "Then nobody will be prepared to compromise with the United States."

He accuses the U.S. of not sticking to its end of the bargain and says Trump is "dissuading European companies from engaging in Iran by threatening them with consequences for their cooperation with Iran."

In Syria's civil war, Iran has long backed President Bashar Assad. Asked about Syria's alleged use of chemical weapons, Zarif references their use by Saddam Hussein's regime against Iranian troops in the 1980-1988 Iran-Iraq war.

"We ask everybody to ... reject the use of chemical weapons, respect international humanitarian law," he says. During the war with Iraq, Iran "never retaliated with the use of chemical weapons. So that's our track record. And that is what we preach."

Zarif also called for an end to the conflict in Yemen, which has seen Iran and Saudi Arabia supporting opposite sides in a bloody civil war that has dragged on for three years.

"What we need to do is put an end to the Yemen conflict," he says. "Iran has been prepared to look and to help achieve a political solution both in Syria and in Yemen."

Zarif said Iran has long called for a cease-fire in Yemen, but Saudi Arabia, he says, wanted a quick military victory there.

"That quick military victory has taken them three years," he says. "So, Saudi Arabia can decide today and stop this bloodshed."