A short timeline of the Islamic State group's rise

April 18, 2010 - US and Iraqi forces kill two leaders of al-Qaeda's branch in Iraq. Abu Bakr al-Baghdadi becomes the franchise's new leader.

March 2011 - Syrian conflict erupts following an uprising against President Bashar Assad that turns into an insurgency and civil war, attracting scores of al-Qaeda militants from Iraq.

April 2013 - Baghdadi announces his group has taken over the Nusra Front, the al-Qaida affiliate in Syria.

The combined group is variously called the Islamic State of Iraq and the Levant, or ISIL, and the Islamic State of Iraq and Syria, or ISIS; eventually it becomes known as the Islamic State group [IS].

Nusra denies the takeover, sparking fighting that continues to this day.

March 5, 2013 - Rebel factions including the Nusra Front take over Raqqa, a provincial capital in north-central Syria, the largest city to be wrested from Assad's government.

May 2013 - IS fighters shoot three people dead in a main square in Raqqa. The group begins seizing towns and villages across northern Syria.

January 2014 - Baghdadi's forces sweep into Fallujah and parts of Ramadi in Iraq's Anbar province, which Iraqi security forces abandoned weeks previously.

In Syria, they seize full control of Raqqa after driving out rival groups. Infighting with rivals erupts across north and eastern Syria.

	An Iraqi gunman stands next the graffiti “IS remains” [Getty]

June 10, 2014 - Baghdadi's fighters take over Iraq's second-largest city, Mosul, and, the next day, overrun more of Nineveh province, including the village of Eski Mosul.

They soon sweep south, capturing Saddam Hussein's hometown of Tikrit and much of the Sunni heartland nearly to the outskirts of Baghdad as government forces melt away.

When they threaten Shia holy sites, Iraq's top Shia cleric issues a call to arms, bringing a flood of volunteers to militias.

June 29, 2014 - IS declares the establishment of a "caliphate," or Islamic state, in territories it controls in Iraq and Syria, and Baghdadi is declared the caliph.

The militants rename themselves "The Islamic State". To celebrate, the group "unites" territories under its control in Iraq and Syria by knocking down sand berms in the desert that mark the border between the two countries.

They later seize several actual border crossings.

August 8, 2014 - The US begins targeting the IS group with airstrikes, citing the humanitarian plight of Iraq's minorities, including the Yazidis.

August 19, 2014 - IS releases a video showing the beheading of American journalist James Foley, reportedly in response to the US-led airstrikes. This marks the first of many videos showing militants beheading foreign captives.

January 23, 2015 - Kurdish peshmerga fighters regain control of Eski Mosul and several neighbouring towns, driving out IS fighters.

January 26, 2015 - Kurdish fighters take control of the Syrian border town of Kobane near Turkey after fighting IS militants for months. US-led airstrikes help turn the tide for the Kurds.

February 3, 2015 - IS releases a video of Jordanian pilot Muaz al-Kassasbeh being burned to death inside a cage. Claims US-led bombing was leading to innocents being burned alive, trapped in their shelled homes.

April 1, 2015 - Backed by US-led coalition airstrikes, Iraqi forces retake the city of Tikrit, their biggest gain yet against the IS group.

May 17, 2015 - Ramadi, the capital of Iraq's Anbar province, falls to IS as Iraqi forces abandon their weapons and armoured vehicles.

May 20, 2015 - IS captures the anicient desert city of Palmyra in central Syria after Assad's forces collapse and withdraw.

June 16, 2015 - Kurds deal the Islamic State group a major setback by capturing the Syrian town of Tal Abyad on the Turkish border, which had provided a strategic supply route for IS.