Efforts between Washington and Tehran to reach an agreement continue to fall short, fueling concerns of return to war.

Donald ⁠Trump says the ceasefire with Iran is “on life support,” after dismissing Tehran’s response to ⁠a US peace proposal as “stupid.” The US president’s swift rejection of Iran’s response on Sunday has fuelled concerns that ⁠the 10-week-old conflict will drag on, and continue to paralyse shipping through the Strait of Hormuz.

Referring to the latest proposal, Trump said the ceasefire is “the weakest right now after reading that piece of garbage they sent us.”

“I didn’t even finish reading it,” he said. “It’s on life support.”

Days after Washington floated a proposal aimed at reopening negotiations, Iran on Sunday released a response focused on ⁠ending the war on all ⁠fronts, including in Lebanon, where US ally Israel is fighting Iran-backed Hezbollah fighters.

Tehran also demanded compensation for war damage, emphasised its sovereignty over ⁠the Strait of Hormuz, called on the United States to ⁠end its naval blockade, guarantee ⁠no further attacks, lift sanctions and remove the ban on Iranian oil sales.

Trump also claimed on Monday that Iran is willing to ‌give the United States “the nuclear dust”, referring to Iran’s enriched uranium stockpile, and said only China and ‌the ‌US have the capability to retrieve it.

Iran’s Foreign Ministry spokesman defended its proposal, saying that Iranian demands are “reasonable”.

“The only thing we have demanded are Iran’s legitimate rights,” Esmaeil Baghaei said on Monday.

The search for an agreement between the US and Iran has so far proved elusive, with Trump threatening a return to war without a series of concessions that Tehran has framed as maximalist and incompatible with its sovereignty. Iranian officials have also expressed a lack of trust in the US, which has previously attacked Iran during periods of negotiation.

“There is a cloud of mistrust when it comes to the United States. Iranians are saying that they were already engaged in negotiations not once, but twice, in the last year, when their country faced this unprecedented campaign of airstrikes by the Americans and the Israelis,” Al Jazeera correspondent Tohid Asadi reported from Tehran. “And now they’re looking for some security assurances, to make sure that this time again they are not going to get into this trap, this vicious circle of war, ceasefire, then another round of conflict.”

Uncertainty around the conflict has continued to unsettle the global economy, as the Strait of Hormuz – the crucial shipping route for oil and gas exports from the Middle East – has effectively remained shut.

The US is blockading Iranian ports in a bid to cut off Iran’s ability to export oil.

“Our demand is legitimate: demanding an end to the war, lifting the [US] blockade and piracy, and releasing Iranian assets that have been unjustly frozen in banks due to US pressure,” Baghaei said.

“Safe passage through the Strait of Hormuz and establishing security in the region and Lebanon were other demands of Iran, which are considered a generous and responsible offer.”