Timeline: How The Iraq Crisis Unfolded
Updated: 9:29am UK, Tuesday 24 June 2014
A look back at the main events in the Iraq crisis, which has seen Sunni insurgents from the Islamic State in Iraq and Syria (ISIS) terror group move to within 50 miles of the capital Baghdad.
December 2011: US troops complete their withdrawal after the 2003 invasion which led to the removal of Saddam Hussein.
August 2013: More than 70 people are killed in attacks at the end of Ramadan. ISIS claim responsibility.
January 2-4, 2014: ISIS declares itself in control of the western city of Fallujah and parts of Ramadi following clashes sparked by the clearing of a Sunni-Arab protest camp.
February: al Qaeda formally disowns ISIS, which was at one time an affiliate, because of its extreme methods.
April: Prime Minister Nouri al Maliki wins the most seats in a general election.
June 10: ISIS seizes all of Nineveh province in the north, including the capital Mosul - Iraq's second city. Mr Maliki asks parliament to declare a state of emergency.
June 11: The militants launch a wave of attacks further south, taking Tikrit and freeing hundreds of prisoners in Baiji. An assault on Samarra, 70 miles (110km) north of Baghdad, is repelled by security forces.
June 12: Iraq's air force strikes fighters' positions near Mosul and Tikrit.
US President Barack Obama says he is looking at "all the options" to help the government, which fails to secure authorisation for a state of emergency.
The army abandons its bases in Kirkuk, leaving Kurdish Peshmerga troops to take control.
June 13: A top Shia cleric issues a call to arms, telling the population to take up arms and defend their country.
Mr Maliki claims government forces have started to clear cities of "terrorists" and implements an emergency plan to protect Baghdad.
President Obama rules out sending back troops to fight ISIS.
The rebels move into the towns of Saadiyah and Jalawla in eastern province of Diyala.
June 14: Iran offers to work with the US to tackle the crisis, as Britain pledges an initial £3m in emergency aid to help refugees fleeing the violence.
The Iraqi army's fightback continues, with forces retaking the towns of Ishaqi, al-Mutasim and Duluiyah in Salaheddin province.
Troops also regain much of Tikrit, Saddam Hussein's home town.
US aircraft carrier USS George HW Bush is ordered to the Persian Gulf.
June 15: Photos emerge appearing to show an ISIS massacre of 1,700 captured government soldiers. Baghdad says number is exaggerated.
Reports say militants have overrun Tal Afar, the largest town in Nineveh province.
A bombing in central Baghdad leaves 15 people dead and dozens injured.
Former PM Tony Blair tells Sky News that critics who believe the violence is the result of the 2003 invasion are "profoundly mistaken".
June 16: Video footage purporting to show an ISIS fighter questioning and killing unarmed Iraqi soldiers draws condemnation.
ISIS takes control of Tal Afar and the al Adhim area of Diyala province.
US Secretary of State John Kerry says Washington is "open to discussions with Iran".
June 17: Britain announces it is reopening its Iranian embassy, with William Hague saying the "circumstances are right" as the West looks to improve relations to help tackle the crisis in Iraq.
Iraq's Shia leaders accuse Saudi Arabia of promoting "genocide" by backing Sunni militants.
June 18: Iraq's foreign minister asks the US to carry out airstrikes to help reverse the sweeping gains of Islamist militants in the country.
David Cameron warns that if Britain does not intervene in the Middle East crisis then terrorists will "hit the UK at home".
Insurgents are seen parading through the city of Baiji with captured vehicles after reports they have taken over three-quarters of Iraq's biggest oil refinery.
ISIS charts its brutality and tactics in annual reports called al-Naba - The Report, it emerges.
June 19: Iraqi authorities say government forces have retaken the Baiji oil refinery after fierce fighting.
Barck Obama says US troops will not return to combat in Iraq, but he would be prepared to take "targeted action".
The president also announces additional equipment and up to 300 additional military advisers could be provided to help fight the ISIS insurgency.
June 20: Iraq's senior Shia religious authority Grand Ayatollah Ali al-Sistani calls for a new government for the country as it struggles to stop Sunni militants.
Barack Obama piles further pressure on Iraq's PM Nouri al Maliki, saying he needs to take urgent steps to heal the sectarian rift in the country, but stopping short of demanding he quit.
A video of British jihadists urging Western Muslims to join ISIS in Iraq and Syria emerges on social media.
June 21: The family of Naseer Muthana, 20, who appears in the ISIS recruitment video and younger brother Aseel, 17, who followed him to fight in the region say they are "devastated".
The men's father Ahmed Muthana tells Sky News he believes his son Nasser was radicalised in a mosque in the United Kingdom.
In Iraq, dozens of Iraqi troops are killed as ISIS militants seize the crucial Qaim crossing into Syria.
A Shia preacher loyal to anti-US cleric Moqtada al Sadr warns that the 300 US military advisers en route to Iraq will be attacked.
June 22: Iran's supreme leader Ayatollah Ali Khamenei comes out in opposition of US intervention in neighbouring Iraq.
President Barack Obama warns ISIS could grow in power, destabilise the region and pose a threat to the US.
The mother of one of two Britons filmed in a militants' video calling for Western Muslims to fight in Syria and Iraq, Reyaad Khan, pleads for him to come home in an emotional Sky News interview.
A former head of counter-terrorism at MI6 tells Sky's Murnaghan programme up to 300 Islamist fighters from Iraq and Syria may have returned to the UK and it would be "impossible" to keep track of all of them.
June 23: Barack Obama warns ISIS could pose a threat to the US, hours after the Islamist militants make dramatic gains by capturing four towns in western Iraq.
US Secretary of State John Kerry arrives in Baghdad for talks with Prime Minister Nouri al Maliki.
June 24: John Kerry arrives in Irbil for talks with Kurdistan's regional government President Massoud Barzani.