Hours after the US and Israel said an air strike killed Ayatollah Ali Khamenei in the military campaign to overthrow the government of the Islamic Republic, its state media confirmed the 86-year-old leader's death on Saturday.
In another blow for Iran's leaders, Armed Forces Chief of Staff Abdolrahim Mousavi was killed in strikes, broadcaster Iran TV said on Sunday.
The US will hit Iran "with a force that has never been seen before", Trump warned on Sunday, if the Middle East nation hits back after the strikes.
"Iran just stated that they are going to hit very hard today, harder than they have ever been hit before," Trump said in a post on Truth Social.
He added, "THEY BETTER NOT DO THAT, HOWEVER, BECAUSE IF THEY DO, WE WILL HIT THEM WITH A FORCE THAT HAS NEVER BEEN SEEN BEFORE!"
Iran's top security official, Ali Larijani, said a temporary leadership council would be set up.
He accused the US and Israel of trying to plunder and disintegrate Iran and warned "secessionist groups" of a harsh response if they attempted action, state television said.
In remarks directed at Trump and Israeli Prime Minister Benjamin Netanyahu, Iran's parliament Speaker Mohammad Baqer Qalibaf said they had crossed a red line and would "pay for it".
Loud blasts were heard for a second day on Sunday in the area of regional business hub Dubai and over Qatar's capital of Doha, witnesses said, after Iran launched retaliatory strikes on the neighbouring Gulf states.
Puffs of white smoke from missile interceptions were glimpsed in the skies over Dubai, while billows of dark smoke rose over its port of Jebel Ali, one of the busiest in the Middle East.
Iran, which has said it would target US bases if attacked, hit a range of other targets, keeping the major oil-producing Gulf on edge.
Air raid sirens sounded repeatedly across Israel early on Sunday, with a series of explosions heard in Tel Aviv as Israel's sophisticated air defence system sought to intercept the latest Iranian offensive.
Trump said the air strikes aimed to end a decades-long threat from Iran and ensure it could not develop a nuclear weapon.
"This is not only Justice for the people of Iran, but for all Great Americans, and those people from many Countries throughout the World, that have been killed or mutilated by Khamenei and his gang of bloodthirsty THUGS," Trump wrote on Truth Social.
Trump and Netanyahu told Iranians the attacks offered them a rare chance to topple their clerical leaders.
The leadership had already been under pressure from an economy hammered by sanctions, protesters who proved ready again to take to the streets despite fierce crackdowns and regional proxies severely weakened by Israeli attacks.
Khamenei was working in his office at the time of Saturday's attack, state media said. It also killed his daughter, grandchild, daughter-in-law and son-in-law.
Experts said the deaths of Khamenei and other Iranian leaders would deal the country a major blow but would not necessarily spell the end of Iran's entrenched clerical rule or the Revolutionary Guards' sway over the population.
Trump evoked the 1979 storming of the US embassy in Tehran, when Iranian student activists in co-ordination with radical clerics took 52 Americans hostage for 444 days, demanding the extradition of the deposed Shah from the US.
Israel's military said it targeted Iran's ballistic missile and air defence systems with strikes on Sunday morning.
Iran's armed forces would soon retaliate again with their biggest offensive against US bases and Israel, the elite Islamic Revolutionary Guard Corps vowed in a statement on Sunday.
Iran responded to Saturday's initial attacks by launching hundreds of missiles and drones targeting US troops and cities in Israel and Arab countries allied with Washington, prompting widespread cancellations of Middle East flights.
Major Middle Eastern airports, including Dubai, the world's busiest international travel hub, were shut on Saturday after the strikes on Iran's missile retaliation unleashed one of global aviation's most severe disruptions in years.
Dubai's landmark Burj Al Arab hotel and the airport, which handles more than 1000 flights a day, were damaged in an overnight attack on sites across the Arab Gulf states that also hit airports in Abu Dhabi and Kuwait.
Tehran warned the Strait of Hormuz, the narrow passage through which one-fifth of global oil consumption passes, had been closed, raising expectations of a sharp jump in oil prices.
OPEC+ major oil producers are set to meet on Sunday and could consider a larger-than-planned output increase as several tanker owners, oil majors and trading houses suspended energy shipments through the Strait.
