By Parisa Hafezi and John Irish

MUSCAT/PARIS (Reuters) - Iran sees its missile programme rather than its uranium enrichment as a bigger obstacle in nuclear talks with the United States that resume on Saturday, an Iranian official with knowledge of the talks said on Friday.

The two sides agreed in talks in Rome last week to begin drawing up a framework to resolve a long standoff over Iran's nuclear programme, with U.S. President Donald Trump threatening to bomb Iran if there is not an agreement.

Iranian negotiators left Rome persuaded that the U.S. had accepted Tehran's position that it would not entirely end its enrichment programme or surrender all the uranium it has enriched already, but that its missile programme remained a big sticking point, the official said.

U.S. Secretary of State Marco Rubio said this week Iran would have to entirely stop enriching uranium under a deal, and import any enriched uranium it needed to fuel its sole functioning atomic energy plant, Bushehr.

The Iranian official described this as "a new media position" and said it would not help in progressing the negotiations.

"The only remaining point of disagreement in the general discussions and mutual understanding is the missile issue," the official said.

The official reiterated Iran's longstanding position that it would not make any further concessions on its missile programme beyond those agreed in a previous deal in 2015, saying Iran's defensive capabilities "are not up for negotiation".

The U.S. State Department declined to comment. The White House did not immediately respond to requests for comment.

Western countries fear Iran's uranium enrichment programme could yield material for an atomic warhead and that it seeks to develop a ballistic missile to carry one.

Iran says its nuclear programme is only for electricity generation and other civilian uses and that it is enriching uranium as fuel for these purposes.

It has denied seeking to create missiles capable of carrying nuclear payloads and says its defence capabilities cannot be open to negotiation in any talks over its atomic programme.

'GESTURE OF GOODWILL'?

Saturday's talks will be held between Iranian Foreign Minister Abbas Araqchi and President Donald Trump's Middle East envoy Steve Witkoff, via an Omani official who will shuttle messages between them in Muscat, Iranian state media said.

They are the third round of talks that started earlier this month in Oman, before moving to Rome.

Trump on Friday said he was willing to meet Iran's Supreme Leader Ayatollah Ali Khamenei or President Masoud Pezeshkian and that he sees the chance of a deal.

During his first term in 2017 Trump ripped up an earlier 2015 Iran nuclear deal that imposed limits on Iran's enrichment programme alongside a monitoring regime in exchange for sanctions relief. The U.N. nuclear watchdog says Iran has since accelerated its enrichment of uranium.

A United Nations Security Council resolution endorsing the 2015 deal also set limits on Iran's missile programme.

The official said Iran's stance that it would not go beyond the requirements of the 2015 deal and resolution mean it would "only refrain from building missiles capable of carrying nuclear warheads as a gesture of goodwill".

Several European diplomats said efforts by their countries to raise Iran's missile programme in sporadic talks over recent months were repeatedly rebuffed by Iranian officials who were insistent that it was not negotiable.

European states have suggested to U.S. negotiators that a comprehensive deal should include limits preventing Iran from acquiring or finalising the capacity to put a nuclear warhead on a ballistic missile, the diplomats said.

(Reporting by Parisa Hafezi in Muscat and John Irish in Paris; additional reporting by Humeyra Pamuk in Washington; Writing by Angus McDowall; Editing by Aidan Lewis)