US President Donald Trump on Sunday announced that the group's elusive leader Abu Bakr al-Baghdadi was killed during a nightime US raid in northern Syria.

Here is a recap:

- 'Caliphate' declared -

The Islamic State of Iraq and the Levant (ISIL) declared in June 2014 that they had set up a caliphate, under the leadership of Baghdadi, in territory seized in Syria and Iraq.

Since January that year they had been in control of Syria's northern city of Raqa. They also seized part of the eastern province of Deir Ezzor, on the Iraqi border, as well as positions in the northern province of Aleppo.

In Iraq, they took Mosul and Sunni Arab areas bordering the autonomous Kurdistan region in the country's north in June.

Raqa and Mosul became the two de-facto IS capitals.

- Atrocities -

Rebranded the Islamic State, they carried out beheadings, mass executions, rapes, abductions and ethnic cleansing in Raqa.

Some of the atrocities were broadcast on video, used as propaganda.

In Iraq, IS seized the historic home of the Yazidi minority in Sinjar region, forcing children to become soldiers and using thousands of women as sex slaves.

- Anti-jihadist coalition -

In August 2014, US warplanes struck IS positions in northern Iraq.

Washington formed a coalition of more than 70 countries to fight the group in both Iraq and Syria, deploying 5,000 soldiers.

- Defeats in Iraq -

In March 2015, Iraq announced the "liberation" of Tikrit, north of Baghdad. In November, coalition-backed Kurdish forces retook Sinjar.

In 2016, Anbar provincial capital Ramadi was retaken, as was the city of Fallujah.

In July 2017, then Iraqi prime minister Haider al-Abadi declared the jihadists' defeat in Mosul.

In December, Abadi announced a final victory against the IS.

- Defeats in Syria -

Kurdish forces drove jihadists out of the city of Kobane, on the Turkish border, in January 2015.

In August 2016, the US-backed Kurdish-Arab alliance known as the Syrian Democratic Forces (SDF) recaptured Manbij in Aleppo province.

Backed by Turkish forces, rebels retook Jarabulus, and then, in February 2017, Al-Bab, the last IS bastion in Aleppo province.

In March 2017, Syrian troops backed by Russian jets took back the ancient town of Palmyra.

In October 2017, the SDF announced the full recapture of Raqa.

The Kurdish-led SDF proclaimed the defeat of the "caliphate" in March 2019 after seizing Baghouz, the IS's final bastion in eastern Syria.

- Baghdadi video -

On April 29, the IS released a video featuring a man said to be Baghdadi, making his first purported appearance in five years, acknowledging IS's defeat in Baghouz while threatening "revenge" attacks.

US Secretary of State Mike Pompeo, on August 20, said the IS group remained a threat in Syria and Iraq, and in some areas had even gained power despite the elimination of their "caliphate".

- Escape of prisoners -

In October a Turkish offensive against Kurdish militants in northern Syria following the withdrawal of US troops from several bases in the area, raised fears of an IS resurgence.

On October 13, Kurdish authorities said nearly 800 relatives of foreign members of IS had escaped from a displacement camp in Ain Issa after a nearby Turkish bombardment.

Ten days later, Washington announced more than 100 IS prisoners had escaped Syria in the chaos since Turkey's incursion.

- Baghdadi's demise -

On Sunday October 27, Trump announces that Baghdadi detonated a suicide vest during an overnight raid by US special forces deep in northwest Syria, killing himself and three of his children.

The US president said the IS leader had been trapped in a tunnel by the special forces and his body had been mutilated by the blast, "but test results gave certain immediate and totally positive identification".

Witnesses had earlier reported nightime gunfire, low flying aircraft and air strikes around the village of Barisha in Idlib province.