Iran's parliament speaker, Mohammad Bagher Ghalibaf, denied that any negotiations with the United States have taken place, accusing Washington of spreading disinformation to manipulate financial and oil markets, on March 23.

The denial came hours after US President Donald Trump posted on Truth Social claiming that Washington and Tehran had held productive conversations over two days focused on ending hostilities, and that he had instructed the Department of War to postpone military strikes against Iranian power plants for five days.

An Israeli official said mediating countries were trying to convene a meeting in Islamabad, with Ghalibaf and other Iranian officials representing Tehran, and Trump's envoy Steve Witkoff, Jared Kushner and possibly Vice President Vance representing Washington.

Iran's foreign ministry said there had been no talks between Iran and the US, while acknowledging some countries in the region were working to reduce tensions.

Ghalibaf, posting on X in a series of messages on March 23, said Iranian officials stood firmly behind the country's supreme leader and vowed to pursue what he called complete punishment of those he described as aggressors.

He also accused the US and Israel of being trapped in a "quagmire" and said false reports of negotiations were being used to engineer favourable moves in commodity and currency markets.

Ghalibaf has emerged as one of Iran's highest-ranking surviving officials following the killing of Supreme Leader Ali Khamenei and severe degradation of the country's military command in US-Israeli strikes late last month.

On March 22, Ghalibaf had warned on X that critical infrastructure and energy facilities across the region could be "irreversibly destroyed" should Iranian power plants be targeted by the US.

Trump postponed the strikes against Iranian power plants for five days on March 23, with Oman's foreign minister saying his country was mediating between the two sides.

US President Donald Trump announced on March 23 that he had ordered a five-day suspension of planned strikes on Iranian power plants and energy infrastructure, he said on social media.

The American president said the US and Iran had held "very good and productive conversations" over the preceding two days aimed at a "complete and total resolution" of the conflict.

The announcement came just hours before Trump's 48-hour ultimatum for Iran to reopen the Strait of Hormuz was due to expire, averting what would have been a major escalation that Iran had warned would trigger "irreversible" destruction of Gulf energy infrastructure.

"Based on the tenor and tone of these in depth, detailed, and constructive conversations, which will continue throughout the week, I have instructed the Department of War to postpone any and all military strikes against Iranian power plants and energy infrastructure for a five day period, subject to the success of the ongoing meetings and discussions," Trump wrote on Truth Social.