Live updates: Trump confirms Baghdadi killed
Predictably, the United States' allies have been lining up to congratulate the US on its operation.
British Prime Minister Boris Johnson called Baghdadi's death "an important moment".
Meanwhile the French Defence Minister said Baghdadi had been handed an "early retirement".
Translation: "Baghdadi: early retirement for a terrorist, but not for his organisation. I congratulate our American allies with this operation. My thoughts thoughts today are for all the victims of the madness of Bagdhadi and the criminals who have followed him."
However Mohammad Javad Azari-Jahromi, Iran's information minister, sounded unimpressed.
"Not a big deal, You just killed your creature," he tweeted, accusing the US of being responsible for Baghdadi's rise.
Baghdadi was born Ibrahim Awad al-Samarrai in 1971 near the Iraqi town of Samarra, as the third of four sons to a Quran teacher who claimed to be a descendent of the Prophet Muhammad.
Apparently a quiet young man who studied Islam and played football, he became one of the most wanted men in the world when in 2014 he declared from Mosul's al-Nuri Mosque that he was ruler of all the land IS had conquered in Syria and Iraq.
Under his leadership, Islamic State murdered thousands and terrorised millions across the world. Middle East Eye takes a look at the now-dead militant here: Abu Bakr al-Baghdadi: The 'loner' who became leader of Islamic State
Trump claimed before and after Baghdadi's killing that the Islamic State group had been destroyed and defeated, but how accurate is that?
Mazloum Abdi, head of the Kurdish-led Syrian Democratic Forces militia that rolled IS back with US backing, said he expects a backlash.
"Sleeper cells will seek revenge for Baghdadi's death," he told the AFP news agency. "This is why anything is possible, including attacks on prisons."
The SDF holds thousands of suspected IS members prisoner in Syria, and has repeatedly raised concern about their security as Turkish forces have staged an assault in the Kurdish-held northeast.
Turkey, the Syrian Kurds and Iraq have all claimed knowledge of the operation, but it seems there may have been other players too.
Trump said Russia, Syria, Turkey and Iraq all assisted in preparations for the raid, which required flying over an hour by helicopter in both directions from an undisclosed base.
The US forces "executed a dangerous and daring nighttime raid in northwestern Syria and accomplished their mission in grand style", Trump said, adding that a US dog was wounded.
“The canine, a beautiful dog, a talented dog, was injured and brought back,” he said.
Speaking to reporters, Trump said Baghdadi "died after running into a dead-end tunnel, whimpering and crying and screaming all the way".
"His body was mutilated by the blast. The tunnel had caved in on it in addition. But test results gave certain immediate and totally positive identification. It was him," the president said.
"The thug who tried so hard to intimidate others spent his last moments in utter fear, in total panic and dread, terrified of the American forces bearing down on him."
"No [US] personnel were lost in the operation while a large number of Baghdadi's fighters and companions were killed with him," Trump added.
US President Donald Trump has confirmed that Abu Bakr al-Baghdadi is dead. He blew himself up using a suicide vest during a US special forces raid, Trump said.
No US personnel were lost in the operation, he said, though many of Baghdadi's companions were killed.
Two Iraqi security sources and two Iranian officials have told Reuters that they have had confirmation that Baghdadi is dead.
One of the Iraqis, speaking anonymously, said the militant leader was discovered after attempting to leave Syria.
"Our sources from inside Syria have confirmed to the Iraqi intelligence team tasked with pursuing Baghdadi that he has been killed with his personal bodyguard in Idlib after his hiding place was discovered when he tried to get his family out of Idlib towards the Turkish border," the Iraqi said.
Baghdadi has been in hiding for years, and was widely expected to be holding up in desert areas of eastern Syria or Iraq. That he has apparently been found in Idlib comes as a surprise.
Iraq reportedly handed Washington information he was there two months ago.
Idlib, which is predominantly controlled by militant group Hay'at Tahrir al-Sham and regularly bombed by Russia and the Syrian government, has seen several raids on al-Qaeda and IS-linked groups.
Video and photographs of the compound attacked overnight show it totally levelled.
The bodies of three men and three women were found in the same location as that purported to be of Baghdadi, a commander of a militant faction in Syria's northwestern province of Idlib told the Reuters news agency.
Meanwhile, Bashira resident Abdel Hameed told AFP he rushed to the scene last night as he heard the helicopters and gunfire.
"The home had collapsed and next to it there was a destroyed tent and vehicle. There were two people killed inside" the car, he said.
According to the Syrian Observatory for Human Rights activist group, a squadron of eight helicopters accompanied by a warplane belonging to the international coalition fighting Islamic State (IS) attacked positions of an al-Qaeda affiliated group in Syria's Idlib province where IS operatives were believed to be hiding.
Newsweek said it had been told by a US army official that Baghdadi, 48, had killed himself by detonating a suicide vest.
It said a brief firefight ensued when US forces entered Baghdadi's compound near Barisha village, some 5km from the Turkish border, and Baghdadi's family members were present.
Citing Pentagon sources, Newsweek said no children were harmed but two of Baghdadi's wives were killed after detonating their own explosive vests.
Below are some of the first images to emerge from Bashira:
Turkey's defence ministry said that Turkish and US military authorities exchanged and coordinated information ahead of the attack.
"Prior to the US operation in Idlib province of Syria last night, information exchange and coordination between the military authorities of both countries took place," the ministry said on Twitter.
Meanwhile, in an apparent reference to the reports surrounding Baghdadi death, Mazloum Abdi, the commander of the Kurdish-led Syrian Democratic Forces (SDF) militia, said a "successful operation" resulted from joint intelligence work with the US.
"An historic, successful operation as a result of joint intelligence work with the United States of America," Abdi said on Twitter.
The United States has carried out an operation in Syria targeting Abu Bakr al-Baghdadi, the leader of the Islamic State group (IS), US officials have said. He is believed to be dead.
Baghdadi, who oversaw the militant group's rise and fall, has been in hiding for years. There have been several claims of his death in the past, but US media are reporting his death with much certainty. US President Donald Trump is set to speak at 13:00 GMT.
The militant leader reportedly killed himself with a suicide vest. You can read Middle East Eye's story on the operation here: Islamic State leader Abu Bakr al-Baghdadi believed dead in US raid
Otherwise MEE will be tracking the the developments throughout the day here on this live blog.