Ali Shamkhani sits in a meeting in Tehran, Iran, on June 12, 2021. (AP)

Iran could halt cooperation with the UN’s nuclear watchdog if external threats persist, an advisor to Iran’s leader, Sayyed Ali Khamenai, warned on Thursday, following renewed threats from US President Donald Trump to use military force if Tehran fails to agree to a nuclear deal.

Iranian and American delegations are expected in Oman on Saturday to begin talks on Tehran’s nuclear program. Trump asserted that he would ultimately decide whether the negotiations are failing, warning it would put Iran in "great danger."

"Continued external threats and putting Iran under the conditions of a military attack could lead to deterrent measures like the expulsion of IAEA inspectors and ceasing cooperation with it," Ali Shamkhani wrote on X.

"Transferring enriched material to safe and undisclosed locations in Iran could also be on the agenda," he added.

While Washington maintains the talks will be direct, Tehran has clarified that the negotiations will be indirect, mediated by Oman’s foreign minister.

During his first term in office (2017–2021), Trump withdrew the US from the 2015 nuclear accord, which limited Iran’s nuclear activity in exchange for sanctions relief, and reimposed broad sanctions. Since then, Iran has significantly exceeded the deal’s uranium enrichment limits, according to the IAEA.

US issues new sanctions on Iran ahead of Oman talks

On Wednesday, the United States imposed new sanctions on five Iranian entities and one individual, accusing them of supporting Iran’s nuclear program, just days after Trump announced plans to initiate discussions with Tehran.

In a statement, the US Department of the Treasury identified the targets, which include the Atomic Energy Organization of Iran and its subsidiary, the Iran Centrifuge Technology Company.

The sanctions also targeted Majid Mosallat, head of Atbin Ista Technical and Engineering Company, whom the Treasury accused of aiding the procurement of foreign components for Iran’s nuclear activities.

The move comes as delegations from Iran and the United States prepare to hold their first round of talks in Oman.

Iranian Foreign Minister Abbas Araghchi said on Tuesday that a deal could be reached if the US approaches the negotiations with goodwill.

While Trump has proposed diplomacy to “make a new deal” to replace the agreement he abandoned during his first term, he has simultaneously reinstated his "maximum pressure" campaign on Iran and threatened military action if negotiations fail.

Tehran condemned the new sanctions and Trump's threats, describing them as contradictory to his stated offer of negotiations.