President Donald Trump has announced that the US has killed Iranian Supreme Leader Ali Khamenei.   

'Khamenei, one of the most evil people in History, is dead,' the president wrote on Truth Social. 

Khamenei, the chief Islamic cleric and ruler of Iran for over 36 years since 1989, has long been an adversary of the US for decades throughout multiple presidential administrations. 

His rule saw the increased Islamification of Iran and the growth of its proxy forces in Yemen, Lebanon, Gaza and beyond. His strong religious views long unsettled the Middle East and placed Iran opposite its more western-embracing neighbors like Saudi Arabia, the United Arab Emirates, Qatar and Bahrain. 

'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,' the statement continued. 

'He was unable to avoid our Intelligence and Highly Sophisticated Tracking Systems and, working closely with Israel, there was not a thing he, or the other leaders that have been killed along with him, could do,' the post went on. 

The president also used his announcement to call on Iranian citizens to stand up to the Islamic regime, saying it is 'the single greatest chance for the Iranian people to take back their Country.'

The definitive proclamation of the supreme leader's death comes after a day of speculation over the 86-year-old's fate following catastrophic US and Israeli strikes on Iran. Now questions swirl over who will be the longtime leader's successor.

There is no single obvious next-in-line who has the support of all the disparate elements of Tehran's clergy, military and political leadership. And some of the potential new leaders may also have been killed in the strikes.

One contender, if he survived the bombardment, is Mojtaba Khamenei, 55, the Ayatollah's second-eldest son.

However, while Mojtaba is a powerful and hardline figure in the background, he has never held government office.

Another option is Ali Larijani, chair of the Supreme National Security Commission who, in recent weeks, Khamenei had given increasing power to instead of President Masoud Pezeshkian. 

Trump told NBC News in an interview that he'd be involved in the process to select Iran's next leader. 

'At some point they'll be calling me to ask who I'd like,' he said, adding he was only being 'a little sarcastic' when saying that.  

Though it appears too early to have any solid indication as to who may come out on top in the power struggle to lead Iran. 

Trump and Israeli Prime Minister Benjamin Netanyahu had reportedly been shown a picture of Khamenei's remains before the president made the official announcement on social media. 

The leader's remains were recovered from rubble at his compound, according to reports. 

Satellite images show black smoke rising and heavy damage at Iranian Supreme Leader Ayatollah Ali Khamenei's compound, following strikes by the United States and Israel against Iran.

Trump's post went on to say that the US strikes 'will continue' for 'as long as necessary.' 

'The heavy and pinpoint bombing, however, will continue, uninterrupted throughout the week or, as long as necessary to achieve our objective of PEACE THROUGHOUT THE MIDDLE EAST AND, INDEED, THE WORLD!' Trump posted. 

Before Trump's statement announcing Khamenei's death, reports of the supreme leader's passing were confirmed by Israeli officials. 

Iran retaliated to the strikes by striking targets in Saudi Arabia, the United Arab Emirates, Bahrain, Kuwait, Jordan, Israel and Qatar.