Abu Bakr al-Baghdadi, the leader of the jihadist group Islamic State (IS) and arguably the world’s most wanted man, killed himself during a raid by US commandos in north-western Syria, President Donald Trump has said.

The self-styled “Caliph Ibrahim” had a $25m (£19m) bounty on his head and had been pursued by the US and its allies since the rise of IS five years ago.

At its peak, IS controlled 88,000 sq km (34,000 sq miles) of territory stretching from western Syria to eastern Iraq, imposed its brutal rule on almost eight million people, and generated billions of dollars in revenue from oil, extortion and kidnapping. But despite the demise of its physical caliphate and its leader, IS remains a battle-hardened and well-disciplined force whose enduring defeat is not assured.

In April 2019, Baghdadi appeared in a video for the first time in almost five years. But rather than speaking from a mosque pulpit in Mosul, this time he was sitting cross-legged on the floor of a room with a rifle by his side. He acknowledged his group’s losses and said IS was now waging a “battle of attrition”, urging supporters to launch attacks to drain its enemies’ human, military, economic, and logistical resources. “They need to know that jihad is continuing until the Day of Resurrection, and that God Almighty ordered us to wage jihad and did not order us to achieve victory.”

It was not clear when or where the video was recorded, but Baghdadi seemed to be in good health. He was seen sitting with at least three other men whose faces were masked or blurred, and going through files on IS branches elsewhere in the world. Analysts saw it as an attempt by Baghdadi to assert that he was still in charge.

No more was heard from him until September, when IS released a purported audio message in which he said “daily operations” were under way on “different fronts”. He also called on supporters to free the thousands of suspected IS militants and tens of thousands of women and children linked to IS who were detained at SDF-run prisons and camps in Syria following the fall of Baghuz. The following month, a Turkish military offensive against the SDF in north-eastern Syria and President Trump’s decision to pull US troops out of the region in response sparked alarm that IS might be able to exploit the security vacuum.

More than 100 prisoners escaped during the offensive and IS sleeper cells carried out several attacks, but Mr Trump rejected criticism of the US withdrawal. “Turkey, Syria, and others in the region must work to ensure that [IS] does not regain any territory,” he insisted. “It’s their neighbourhood; they have to maintain it.”

Early on 23 October, US special operations forces carried out a raid outside the village of Barisha, in the north-western Syrian province of Idlib – the last stronghold of the opposition to President Assad. The target of the raid was Baghdadi, despite the area being hundreds of kilometres from the place where he was believed to be hiding.

President Trump later told reporters that Baghdadi had retreated into a tunnel with three children during the raid and then detonated an explosive vest when US military dogs were sent in, killing all four of them. Baghdadi’s body was mutilated by the blast, but test results gave certain and positive identification, he said. “A brutal killer, one who has caused so much hardship and death, was violently eliminated – he will never again harm another innocent man, woman or child,” Mr Trump declared. “He died like a dog. He died like a coward. The world is now a much safer place.”

There was no immediate confirmation of Baghdadi’s death from IS.