Haley: Trump's Iran deal criticism is not a clear sign he'll withdraw

He said Iran was complying with the deal but businesses had been reluctant to commit to investments and contracts out of concern that the United States could re-impose sanctions under the agreement's "snapback provision". They tell NBC News that he's leaning toward decertifying the deal before the next compliance deadline on October 15.

Gabriel, speaking on the sidelines of a United Nations meeting, said world powers had every interest in maintaining the 2015 deal and much work would be needed in coming weeks to ensure it remained in force.

"It would be a great pity if this agreement were to be destroyed by rogue newcomers to the world of politics", Rouhani said of the nuclear accord.

"Clearly, what the Iranians try to do is make their president look like the good guy", Bays said, adding that the word moderation was repeated throughout Rouhani's speech.

Of the 193 countries present at the annual United Nations conference it was only Israeli Prime Minister Benjamin Netanyahu and his team who were smiling when Trump made his debut speech at the UN. He'll be joined by the USA envoy to the UN, Nikki Haley.

The hardline politician has been a vocal opponent of the nuclear deal, which was signed two years ago in Vienna between Iran and the world powers.

The nuclear deal with Iran has always been a point of contention, especially among Republicans who opposed it.

In an apparent reference to the recent criticism of the deal by US President Donald Trump, who has labeled the landmark agreement "worst deal ever negotiated" while vowing to scrap it, Mogherini argued that "there is no need to renegotiate parts of the agreement".

The prospect of Washington reneging on the agreement has anxious some USA partners that helped negotiate it, especially as the world grapples with another nuclear crisis, North Korea's nuclear and ballistic missile development.

Gabriel told reporters any US move to cancel the Iran deal and impose new sanctions on Tehran would discourage powers such as North Korea from negotiating an end to their own nuclear programmes.

Iran's President Hassan Rouhani is to address the United Nations General Assembly, where anxious world leaders are fearful of a new stand-off even as they grapple with the North Korean menace.

Iranian President Hassan Rowhani said on Wednesday that Tehran would respond "decisively and forcefully to any violation by any party to the nuclear agreement", stressing that "Iran will not be the first to violate the nuclear agreement".

Trump spoke to Chinese President Xi Jinping earlier on Monday and committed to keep up pressure on North Korea by enforcing United Nations resolutions, the White House said.

European Union foreign policy chief Federica Mogherini confirmed Zarif's remarks, stressing that the nuclear agreement was "delivering" despite calls by Washington to renegotiate it.

Trump blasted the Iranian government as a "murderous regime" on the "pursuit of death and destruction".

"I don't know whether I could have the same kind of matter of fact discussion with North Korea because we don't know how their means of communication and behavior will be".