Tehran, May 2 : Iran's Foreign Ministry spokesman Esmaeil Baghaei has said that the fourth round of indirect nuclear talks with the US, scheduled for Saturday in Rome, has been postponed at the mediator Oman's proposal.

He made the announcement on Thursday in an address to reporters, adding that the new dates would be announced later, according to a statement by the Ministry.

Baghaei reaffirmed Iran's determination to use diplomacy to safeguard the nation's "legitimate and legal" interests and to end the sanctions and economic pressure against Iran, Xinhua news agency reported.

The spokesman stressed that "since entering the talks with goodwill, the Iranian delegation has been discussing specific frameworks based on the country's principled positions under international law regarding using nuclear energy peacefully and ending illegal sanctions, demonstrating its seriousness in result-oriented talks aimed at achieving a just, rational, and sustainable agreement".

Earlier in the day, Omani Foreign Minister Sayyid Badr bin Hamad Al Busaidi officially announced on social media platform X that the fourth round of the Iran-US talks scheduled for Saturday had been postponed for "logistical reasons," adding, "New dates will be announced when mutually agreed."

The administration of President Donald Trump has said its aim is to prevent Iran from developing a nuclear weapon, though Tehran has long denied armament as a goal. It frames its nuclear programme as a civilian energy project.

The Trump White House has hinted its goals may extend further, though, to the total dismantlement of Iran's nuclear enrichment programme.

In mid-April, US special envoy Steve Witkoff released a statement saying that "Iran must stop and eliminate its nuclear enrichment and weaponisation program" as part of a final deal.

Earlier on Thursday, before the postponement was announced, Iran accused the US of issuing "contradictory behaviour and provocative statements" about the nuclear negotiations.

And on Wednesday, the US made a series of aggressive moves as part of its "maximum pressure" campaign against Iran, heightening the already uneasy relations.

First, the US Department of State sanctioned seven entities involved in the trade of Iranian oil products, on the basis that the proceeds "support its terrorist activities and proxies". Then, Defence Secretary Pete Hegseth offered his own remarks, warning that Iranian support of the Houthis, a Yemen-based armed group, could result in US retaliation.

"Message to IRAN: We see your LETHAL support to The Houthis. We know exactly what you are doing," Hegseth wrote on social media on Wednesday.

"You know very well what the US Military is capable of ' and you were warned. You will pay the CONSEQUENCE at the time and place of our choosing."

Trump himself later chimed in with a social media message on Thursday, warning the international community to stop its purchases of Iranian oil products.

"Any Country or person who buys ANY AMOUNT of OIL or PETROCHEMICALS from Iran will be subject to, immediately, Secondary Sanctions. They will not be allowed to do business with the United States of America in any way, shape, or form," Trump wrote.

Despite the heated rhetoric, Iran's Ministry of Foreign Affairs said that Thursday's postponement came "at the request of Oman's Foreign Minister".

Iranian spokesperson Esmail Baghaei also emphasised that his country was committed to achieving "a fair and lasting agreement" with the US.

Successive US administrations have sought to prevent Iran from acquiring a nuclear weapon. One recent effort culminated with a 2015 agreement called the Joint Comprehensive Plan of Action (JCPOA).

The multilateral agreement, forged during the administration of US President Barack Obama, created a framework for Iran to receive relief from international sanctions, in exchange for reducing its uranium enrichment and submitting to inspections of its nuclear facilities.

But when Trump succeeded Obama as US President, he set into motion plans to withdraw the US from the JCPOA in 2018, causing the deal to crumble.

Instead, during his first term as President from 2017 to 2021, Trump pursued a campaign of "maximum pressure" against Iran, a strategy he has returned to since taking office a second time in January.

Oman has been facilitating the dialogue between Iran and the US to help narrow differences between the two countries and promote regional stability.

With the Omani mediation, the first and third rounds of Iran-US talks were held in the Omani capital Muscat on April 12 and April 26, and the second one in Rome on April 19.

/IANS