Tehran (AFP) - Iran’s supreme leader on Saturday vowed revenge for the US-Israeli killing of his father and predecessor, hours after President Donald Trump threatened severe reprisals in the event of any attempt on his own life.

Both sides dialled up the rhetoric after exchanges of fire this week rocked an interim agreement aimed at ending the Middle East war, which broke out in late February with massive US-Israeli strikes that killed former supreme leader Ali Khamenei.

Trump has declared their ceasefire over while leaving the door open for talks, and mediators have been trying to salvage a diplomatic solution, with Iranian media reporting that a delegation from Qatar travelled to Iran on Friday.

“Vengeance is the will of our nation and must inevitably be carried out,” new supreme leader Mojtaba Khamenei said in a written message.

“This matter depends neither on my personal existence nor on that of other officials. Whether we are present or not, it will come to pass,” he wrote in his first message since his father’s funeral this week.

He said Iran had compiled a list of individuals to be targeted.

Khamenei has not been seen in public since before the war, and was reportedly wounded in the strikes that killed his father.

Hours earlier, Trump had posted on his Truth Social platform that any attempt to assassinate him would lead the United States to “completely decimate” Iran.

“1000 Missiles are Locked and Loaded and aimed at the Islamic Republic of Iran, with thousands of more to immediately follow, should the Iranian Government act on its threat, pronounced in many corners of the Globe, to assassinate, or attempt to assassinate, the sitting President of the United States of America, in this case, ME!,” he wrote.

With the threats flying, mediators have been working to bring diplomacy back on track. Iran’s Tasnim news agency reported on Friday that a Qatari delegation was visiting Iran to “try to reinforce Qatar’s role as a mediator”.

Trump has said talks with Iran will continue but has labelled them “a waste of time”.

Iran’s Foreign Minister Abbas Araghchi insisted Tehran had stuck to its end of the bargain under the memorandum of understanding (MoU) struck between the warring parties last month, adding: “There can only be mutual compliance.”

Iran’s ambassador to the UN, Amir Saeid Iravani, said on Friday that it remained committed to the deal, “provided that the United States fully and faithfully complies with its own obligations”.

“However, should the United States continue to violate its obligations under the MoU, Iran will no longer be bound to fulfill its obligation under the MoU,” he added.

- Hormuz deadline -

A key roadblock to a final agreement is the future of the Strait of Hormuz, which Iran closed to commercial shipping during the war.

The waterway is a key conduit for oil and gas exports out of the energy-rich Gulf, and its closure has heavily impacted the world economy.

Iran insists on controlling the passage of ships and has announced plans to charge fees, saying there will be no return to the free navigation of the pre-war era – a stance Washington has rejected.

Under customary international law, states are not generally permitted to charge tolls on straits used for international navigation.

Araghchi on Saturday arrived in Oman, which sits on the other side of Hormuz, for talks on administering the strait.

Iranian state TV said he and his Omani counterpart “exchanged views on appropriate mechanisms to ensure the safe passage of ships through” the waterway.

News outlets Axios and Politico reported that Washington has given Tehran until Saturday to stop firing on commercial ships transiting Hormuz and acknowledge the waterway is open.

Axios journalist Barak Ravid reported Qatari officials were also taking part in the Oman talks, with a potential statement on fully reopening the strait’s “median lane” under discussion.

This week’s exchange of strikes was sparked after Iran was accused of targeting three vessels it said had deviated from its approved route.

- ‘Hard-earned peace’ -

Despite being one of the Gulf nations targeted during the war, Qatar has spearheaded efforts to get diplomacy back on track.

Its emir on Friday held a call with Prime Minister Shehbaz Sharif of Pakistan, which has also been mediating, according to Sharif’s office.

The Pakistani leader said he had also spoken with Iran’s President Masoud Pezeshkian, urging him to safeguard the “hard-earned peace” in the region.

But Iran’s chief negotiator in talks with Washington, Mohammad Bagher Ghalibaf, struck a defiant tone.

“Ending the war is a priority for the countries of the world, but everyone must know that this confrontation will never end with Iran’s surrender,” Iran’s ISNA news agency quoted him as saying.

Iranians, he said, were “fully prepared to defend ourselves”.

burs-axn/smw