The latest hurdle came hours after Israel -- which launched the war against Iran alongside the US in February -- carried out strikes targeting Beirut's southern suburbs. One of the strikes hit the Ghobeiry neighbourhood, killing at least three people and wounding six others, Lebanon's state media and civil defence agency reported. Tel Aviv later confirmed the attack on Beirut and issued forced displacement orders for 29 villages in southern Lebanon.
Iran's Parliament Speaker and chief negotiator, Mohammad Bagher Ghalibaf, condemned Washington for failing to restrain Israel just as reports indicated a peace deal was imminent.
"The Zionists' aggression against Dahieh once again showed that the United States either lacks the will to implement its commitments or lacks the ability to do so," Ghalibaf wrote on X.
"If you do not have the will or the ability to fulfil your commitments, then there is no point in talking about continuing down this path."
The US president had previously said a deal to end the war in the Middle East would be signed as early as Sunday and that the blockaded Strait of Hormuz would reopen immediately, though Iran had offered a less concrete timeline.
Trump -- who over weeks of negotiations repeatedly declared a deal with Iran was all but concluded -- had said on Saturday that the accord was "scheduled to get signed tomorrow, and immediately after it is signed, the Hormuz Strait is OPEN TO ALL".
But Iran has insisted that any agreement to end the Middle East war also include an end to Israel's war on Lebanon, and Israel's last strikes on the Lebanese capital a week ago drew a retaliatory Iranian missile barrage.
Iranian Brigadier General Mohammad Jafar Asadi said the latest Israeli strikes "will not go unanswered".
A US official said Friday that the deal on the table included Lebanon, where Israeli strikes have killed more than 3,600 people since March 2.
A statement from the foreign ministry of Pakistan, which has been a key mediator between the warring parties, had also said that the deal's signing was planned for Sunday.
But Iran's Fars news agency, citing "a well-informed source close to the Iranian negotiating team", reported Sunday that Tehran had "not yet taken or announced its final decision".
Iranian foreign ministry spokesman Esmaeil Baqaei had said the day before that the deal would not be signed Sunday, but added: "The possibility of this happening in the coming days cannot be ruled out."
A delegation from fellow mediator Qatar arrived in Tehran on Sunday "to help facilitate the finalisation of the agreement", a diplomat with knowledge of the situation told AFP.
The warring parties have released conflicting information about the contents of the deal, as each seeks to show it emerged from the war with the upper hand.
Tehran has insisted it will maintain control over the Strait of Hormuz, but the US has repeatedly said this would be unacceptable.
Since imposing its blockade on the strait -- which has thrown global markets into turmoil -- Iran has demanded vessels obtain permission from its armed forces before transiting the waterway, and has established a new body to oversee it and collect tolls.
The US has responded with its own blockade of Iranian ports.
Iran's Foreign Minister Abbas Araghchi had said on Friday that the deal on the table called for the lifting of the US naval blockade.
Another key sticking point in the talks has been the fate of Iran's nuclear programme, particularly its stockpile of highly enriched uranium -- believed to have been buried by US strikes last year.
Iran has long insisted its nuclear programme is peaceful, but the US, Israel and other Western governments suspect it of seeking a bomb.
Araghchi on Friday said the only way to deal with Iran's enriched uranium "is to dilute it inside Iran".
Trump, who has justified the war as necessary to prevent Iran from obtaining nuclear weapons, previously said the US would remove and destroy the uranium.
On Saturday, he said: "When all is calm, we will go in and get the Nuclear Dust... and downblend and destroy it, whether in Iran or the United States."
Israeli Prime Minister Benjamin Netanyahu said Trump had promised him any agreement would include the removal of the enriched nuclear material.
*This story was edited by Ahram Online.
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