Iran has signaled to six world powers that it is open to talks about its ballistic missile arsenal, seeking to reduce tension over the disputed program, Iranian and Western officials familiar with the overtures told Reuters. Iran denied the report, saying its ballistic missile program was for defense purposes only and was non-negotiable.

Tehran has repeatedly vowed to continue building up what it calls defensive missile capability in defiance of Western criticism, with Washington saying the Islamic Republic's stance violates its 2015 nuclear deal with the powers.

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But the sources said that given U.S. President Donald Trump's threats to ditch the deal reached under his predecessor Barack Obama, Tehran had approached the powers recently about possible talks on some "dimensions" of its missile program.

"During their meeting on the sidelines of the UN General Assembly last month, Iran told members of the (world powers) that it could discuss the missile program to remove concerns," an Iranian source with knowledge of the meeting told Reuters on condition of anonymity.

U.S. and Western officials did not confirm the matter was discussed at the Zarif-Tillerson meeting. But two U.S. officials said Iran had recently been "keeping it alive" by feeding certain media reports and via third parties such as Oman.

Open gallery view U.S. President Donald Trump addresses the United Nations General Assembly at UN headquarters, September 19, 2017. Credit: Drew Angerer/AFP

Iran's Mehr news agency quoted Foreign Ministry spokesman Bahram Qasemi as denying the report, saying "Iran has in all bilateral diplomatic meetings ... emphasized that its defensive missile program is not negotiable and that it is not inconsistent with UN Security Council resolution 2231," which endorsed the nuclear deal.

Iran's reported approach came after Trump called the nuclear accord "an embarrassment" and "the worst deal ever negotiated". He is expected to announce soon that he will decertify the deal, a senior administration official said on Thursday.

Such a step could unravel the breakthrough agreement - seen by supporters as crucial to forestalling a Middle East arms race and tamping down regional tensions since it limits Iran's ability to enrich uranium in exchange for sanctions relief.

The other five powers are Britain, France, Germany, Russia and China, all of whom have reaffirmed commitment to the deal.

U.S. Secretary of Defense James Mattis said Tuesday that remaining a party to the nuclear deal with Iran is in the United States' national security interests.



World powers talks with Iran

Iranian Foreign Minister Mohammad Javad Zarif met his counterparts from the six powers, including U.S. Secretary of State Rex Tillerson for the first time, on the fringes of the U.N. gathering on Sept. 20.

"The Americans expressed their worries about Iran's missile capability and Zarif said in reply that the program could be discussed," the Iranian source told Reuters.

A U.S. official with first-hand knowledge of dealings with the Islamic Republic said Zarif had been recycling offers that "have been lying dormant on the table for some time.

"Zarif knows that if Trump goes ahead and decertifies Iran, it (Iran) will be on the high ground, and the U.S. will be isolated among the (six powers)," the official said.

The Iranian Foreign Ministry refused to comment on the reported overture. The U.S. State Department declined comment on whether possible talks on missiles were addressed at the meeting or whether Iran had recently communicated such interest.

The U.S. mission at the United Nations referred Reuters to the State Department for comment.

The Trump administration has imposed fresh unilateral sanctions on Iran, saying its missile tests violate the UN resolution that formalized the nuclear deal. It calls on Tehran not to undertake activities related to missiles capable of delivering atom bombs. Iran says it has no such plans.

A State Department official said Washington remained committed to "countering the full range of threats the Iranian regime poses to the U.S., our allies, and regional stability, including its ballistic missile development".

Iran has one of the biggest ballistic missile programs in the Middle East, viewing it as an essential precautionary defense against the United States and other adversaries, primarily Gulf Arab states and Israel.

The United States and its allies worry that such missiles could potentially carry nuclear warheads, should Iran ever develop the means to assemble atomic bombs - a scenario the 2015 nuclear accord was designed to prevent.