DUBAI (Reuters) - Iran’s right to enrich uranium is not negotiable, Foreign Minister Abbas Araqchi said on Wednesday ahead of a second round of talks set to take place in Rome this weekend with the United States about Tehran’s disputed nuclear programme.

The talks, which began in Oman on Saturday with the Gulf state acting as mediator, are the first between the two adversaries under U.S. President Donald Trump, who has threatened military action if there is no deal.

Araqchi was responding to a comment made on Tuesday by top U.S. negotiator Steve Witkoff, who said the Islamic Republic must "stop and eliminate its nuclear enrichment" to reach a deal with Washington.

"We have heard contradictory statements from Witkoff, but real positions will be made clear at the negotiating table," Araqchi was quoted by Iranian state media as saying in Tehran.

"We are ready to build trust regarding possible concerns over Iran’s enrichment, but the principle of enrichment is not negotiable."

Last weekend’s U.S.-Iran talks in Oman were described by both sides as positive and constructive.

Western powers say Iran is refining uranium to a high degree of fissile purity beyond what is justifiable for a civilian energy programme and close to the level suitable for atomic bomb fuel. Iran has long denied seeking nuclear weapons.

Iranian media said on Wednesday, without citing sources, that the second round of talks would be held in the Italian capital Rome on Saturday. It was earlier announced that the talks would resume in Oman.

Sources briefed on the matter confirmed the change of venue to Reuters.

Iran’s foreign ministry spokesperson Esmaeil Baghaei compared the venue of the Iran-US nuclear talks to a goalpost in a post on X on Wednesday, saying moving it might "jeopardize any beginning" and that changing it was a "professional error".

A diplomatic source said Rafael Grossi, director general of the International Atomic Energy Agency, the U.N. nuclear watchdog whose inspectors monitor Iranian nuclear sites, had also been invited to Rome for the occasion of the talks.

Italian Foreign Minister Antonio Tajani confirmed the talks would be in held in Rome but said Italy would not be involved.

"Italy simply wants to be a bridge for peace; we have no ambitions of any kind. Such a delicate negotiation is up to the parties involved and their willingness to achieve a concrete result," Tajani said in a statement.

On Thursday Araqchi will deliver a message from Iranian Supreme Leader Ali Khamenei to Russian President Vladimir Putin during a trip to Russia, state media reported.

"Amidst important global developments, close, continuous and trusting communication between Iranian and Russian authorities will serve regional as well as international peace and stability," Iranian Ambassador Kazem Jalali wrote on X.

The Kremlin on Tuesday declined to comment when asked if Russia was ready to take control of Iran’s stocks of enriched uranium as part of a possible future nuclear deal between Iran and the United States.

Britain’s Guardian newspaper reported that Tehran was expected to reject a U.S. proposal to transfer its stockpile of enriched uranium to a third country such as Russia as part of an deal Washington is seeking to curb Iran’s nuclear activity.