- Video report by ITV News Security Editor Rohit Kachroo
The leader of so-called Islamic State is dead after being targeted by a US military raid in Syria, President Donald Trump has declared.
The president said Abu Bakr al-Baghdadi "died like a dog, died like a coward" in a night-time raid after detonating a suicide vest, alongside three of his children.
"He died after diving into a dead-end tunnel - whimpering and crying and screaming all the way," said Mr Trump.
"He had dragged three of his young children with him, they were led to certain death. He reached the end of the tunnel as our dogs chased him down.
"He ignited his vest, killing himself and the three children."
Mr Trump said the US had been "searching for Baghdadi for many years" and "capturing and killing" the IS leader had been his national security priority.
The president said tests on the remains confirmed it was al-Baghdadi, with DNA taken for "on-site tests."
Mr Trump said: "There were body parts, not much left, but there were substantial pieces."
It was confirmed through DNA that it was him about 15 minutes after the death.
President Trump said there were 11 children in the compound who were taken to safety and two women, who died.
"Both wives [of Baghdadi], both wearing vests, both are dead," he added.
Mr Trump said no military personnel were injured in the operation, but a military dog had been injured.
The president said the US had al-Baghdadi under surveillance for several weeks and during the raid forces flew low and fast, and were met with gunfire at points.
The president said security officials were already aware of who would be in line to succeed al-Baghdadi and that "we already have them in our sights".
- Video shows the remains of various buildings where the raid apparently took place
Planning for the operation began two weeks ago, Trump said, after the US gained unspecified intelligence on al-Baghdadi's whereabouts.
Eight military helicopters flew for more than an hour over territory controlled by Russian and Syrian forces, Trump said, before landing under gunfire at the compound.
Trump said he watched the operation from the White House Situation room as it played out live "as though you were watching a movie".
He said US forces breached the walls of the building because the doors were booby-trapped and chased al-Baghdadi into the tunnel, which partially collapsed after al-Baghdadi detonated the suicide vest.
Trump said a military dog was injured by the explosive blast. He also revealed that US personnel spent roughly two hours on the ground collecting intelligence.
He suggested he may order the release of the video so that the world knows al-Baghdadi did not die of a hero and spent his final moments "crying, whimpering and screaming".
- Baghdadi's death is "exceptionally timely" for the US President, says ITV News Washington Correspondent Robert Moore
British Prime Minister Boris Johnson said: "The death of Baghdadi is an important moment in our fight against terror but the battle against the evil of Daesh is not yet over.
"We will work with our coalition partners to bring an end to the murderous, barbaric activities of Daesh once and for all."
A senior Turkish official said "to the best of my knowledge" al-Baghdadi arrived at a location in Syria 48 hours prior to the raid.
The Turkish official said there has been "close coordination" among relevant parties and the Turkish military had advanced knowledge of the raid in Syria’s Idlib province.
Mr Trump had earlier teased a major announcement, tweeting on Saturday night that “Something very big has just happened!”
The strike came amid concerns that a recent American pullback from northeastern Syria could infuse new strength into the militant group, which had lost vast stretches of territory it had once controlled.
Al-Baghdadi lead IS for the last five years, presiding over its ascendancy as it cultivated a reputation for beheadings and attracted hundreds of thousands of followers to a sprawling and self-styled caliphate in Iraq and Syria.
The Syrian Observatory for Human Rights, a Syria war monitor, reported an attack carried out by a squadron of eight helicopters accompanied by a warplane, in the Barisha area north of Idlib city, after midnight on Saturday.
The war monitor said the helicopters targeted IS positions with heavy strikes for about two hours.
The Britain-based Observatory, which operates through a network of activists on the ground, documented the death of nine people as a result of the coalition helicopter attack.
Al Baghdadi's presence in the village, which is a few kilometers away from the Turkish border, would come as a surprise, even if some IS leaders are believed to have fled to Idlib after losing their last sliver of territory in Syria to US-allied Kurdish forces in March.
The surrounding areas are largely controlled by a rival of the Islamic State grou, the al-Qaeda-linked Hayat Tahrir al-Sham, although other jihadi groups sympathetic to IS operate there.
Unverified video circulated online by Syrian groups appeared to support the Observatory claim that the operation occurred in Barisha.
The intelligence source on the militant leader's whereabouts could not be immediately confirmed, but both Iraqi and Kurdish officials claimed a role.
The Turkish military also tweeted that prior to the operation in Idlib, it exchanged "information" and coordinated with US military authorities.
Kurdish forces appeared ready to portray al-Baghdadi's death as a joint victory for their faltering alliance with the US, weeks after Trump ordered American forces to withdraw from northeastern Syria, all but abandoning Washington's allies to a wide-ranging Turkish assault.
The commander of the Kurdish-led Syrian Democratic Forces, Mazloum Abdi, tweeted: "Successful& historical operation due to a joint intelligence work with the United States of America."
He remained among the few IS commanders still at large despite multiple claims in recent years about his death and even as his so-called caliphate dramatically shrank, with many supporters who joined the cause either imprisoned or jailed.
His exhortations were instrumental in inspiring terrorist attacks in the heart of Europe and in the United States.
Shifting away from the airline hijackings and other mass-casualty attacks that came to define al-Qaeda, al-Baghdadi and other IS leaders supported smaller-scale acts of violence that would be harder for law enforcement to prepare for and prevent.
They encouraged jihadists who could not travel to the caliphate to kill where they were, with whatever weapon they had at their disposal.
In the US, multiple extremists have pledged their allegiance to al-Baghdadi on social media, including a woman who along with her husband committed a 2015 massacre at a holiday party in San Bernardino, California.
With a $25 million (£19.5 million) bounty on his head, al-Baghdadi had been far less visible in recent years, releasing only sporadic audio recordings, including one just last month in which he called on members of the extremist group to do all they could to free IS detainees and women held in jails and camps.
The purported audio was his first public statement since last April, when he appeared in a video for the first time in five years.