United States President Donald Trump has announced an extension to the ceasefire with Iran, saying that the US military will hold off its planned attack to allow more time for Tehran to put forward a proposal to end the war.

The move on Tuesday comes at the request of Pakistani mediators, according to Trump. The truce was set to expire on Wednesday.

“I have therefore directed our Military to continue the Blockade and, in all other respects, remain ready and able, and will therefore extend the Ceasefire until such time as their proposal is submitted, and discussions are concluded, one way or the other,” the US president said in a social media post.

Without a specific deadline, Trump’s statement suggests that the truce’s extension is open-ended, at least from the US side.

Iran did not issue an immediate response to Trump’s statement. The semi-official Tasnim news agency said Tehran’s position will be “officially announced later”.

The extension marks the latest abrupt reversal from the Trump White House. Hours before his social media post, Trump had said that he opposed lengthening the truce, warning Iran that time is running out before the US launches a huge attack on its infrastructure.

The about-face came as Iranian officials condemned the US naval blockade on the country’s ports, putting in doubt their participation in talks scheduled for Wednesday.

Afterwards, Pakistani Prime Minister Shehbaz Sharif expressed gratitude to Trump for agreeing to prolong the truce, saying that Islamabad will continue to push for a negotiated settlement to the conflict.

“I sincerely hope that both sides will continue to observe the ceasefire and be able to conclude a comprehensive ‘Peace Deal’ during the second round of talks scheduled at Islamabad for a permanent end to the conflict,” Sharif said in a post on X.

With the naval siege persisting, it is unclear whether the extension of the truce will be enough to bring Iran to the negotiating table in Islamabad.

Earlier on Tuesday, Iran’s Minister of Foreign Affairs Abbas Araghchi called blockading Iranian ports an “act of war” and a violation of the existing ceasefire.

“Iran knows how to neutralize restrictions, how to defend its interests, and how to resist bullying,” Araghchi wrote.

Although the Iranian position has publicly been to reject US threats and its naval siege, Trump suggested that disagreements within the leadership in Tehran are slowing down diplomatic efforts.

“Based on the fact that the Government of Iran is seriously fractured, not unexpectedly so and, upon the request of Field Marshal Asim Munir, and Prime Minister Shehbaz Sharif, of Pakistan, we have been asked to hold our Attack on the Country of Iran until such time as their leaders and representatives can come up with a unified proposal,” the US president wrote in Tuesday’s message.

Since the US and Israel first launched strikes against Iran on February 28, multiple top Iranian officials have been killed, including Supreme Leader Ali Khamenei.

But there have nevertheless been no major defections in the governing system in Tehran, with the Islamic Revolutionary Guard Corps (IRGC) spearheading the war effort.

Khamenei was replaced by his son, Mojtaba, who has yet to make a public appearance since his selection as supreme leader last month.

Reporting from Tehran, Al Jazeera correspondent Ali Hashem explained that Trump’s assertion about fractures in the Iranian leadership is likely a “misconception”.

“Iran has a very unified leadership since the assassination of former Supreme Leader Ayatollah Ali Khamenei,” Hashem said.

“Why? Because the new leader, Mojtaba Khamenei, and the circle around him are a team that’s been working together for the past 15 years. Members of this team are currently in the centres of decision in Tehran.”

Iran and the US agreed to an initial two-week ceasefire on April 8, but the deal has been marred by disagreements over the inclusion of Lebanon in the truce and control of the Strait of Hormuz, leading to persisting tensions.

To end the war, the US is seeking a complete shutdown of Iran’s nuclear programme as well as limits on its missile production and its support for regional allies, including Hezbollah and Hamas.

But Tehran has insisted on its right to enrich uranium domestically as part of a civilian nuclear programme. It also ruled out using its military capabilities and regional alliances as concessions.

Another sticking point is Iran’s existing stockpiles of highly enriched uranium.

Trump has claimed that Tehran agreed to the US extracting nuclear material from bombed sites. But Iran has said that it will not allow the uranium to leave the country.

Barbara Slavin, a distinguished fellow at the Stimson Center think tank, said Trump’s statement extending the ceasefire is a “way to cover the embarrassment” of floundering negotiations.

She pointed out that Trump was willing to send Vice President JD Vance to negotiate with Iran in Pakistan, but Tehran did not appear ready to show up at the talks.

“This war hasn’t gone the way he expected from the very beginning, and Iran has discovered new leverage in its control of the Strait of Hormuz,” Slavin told Al Jazeera.

The US should “relinquish its maximalist demands” and offer Iran “some sort of gesture that it is serious in seeking a resolution”, she added.