BAGHDAD - The Islamic State in Iraq and Syria (ISIS) militant group launched a sweeping offensive a year ago that overran large chunks of Iraqi territory, led to thousands of deaths and displaced millions of people.
These are some key events in the conflict as we approach the one-year anniversary of the offensive:
June 9: ISIS-led offensive begins in Iraq's second city Mosul. June 10: Mosul falls and the surrounding province of Nineveh follows as multiple Iraqi security forces divisions collapse. Then Premier Nuri al-Maliki announces the government will arm citizens who volunteer to fight.
June 11: Tikrit, another major city north of Baghdad, falls.
June 13: Grand Ayatollah Ali al-Sistani, Iraq's top Shi'ite cleric, calls on Iraqis to take up arms against ISIS.
ISIS claims it has executed 1,700 mainly Shi'ite recruits, releasing photos showing the killings.
June 29: ISIS declares a cross-border Islamic "caliphate" in Iraq and Syria, headed by leader Abu Bakr al-Baghdadi.
Aug 2: ISIS launches a renewed northern offensive, driving Iraqi Kurdish forces back and targeting minority groups with mass killings, enslavement and rape.
Thousands of members of the Yazidi religious minority are besieged on Mount Sinjar, drawing international concern and calls for intervention.
Aug 8: US begins air strikes in Iraq. An international coalition follows suit.
Aug 14: Mr Maliki, whose policies helped fuel ISIS' rise, steps aside, and is replaced by Mr Haider al-Abadi.
Aug 19: ISIS says it has beheaded United States journalist James Foley, releasing a video of the killing.
Similar shocking beheadings take the lives of journalists Steven Sotloff, Kenji Goto, aid workers David Haines, Alan Henning and Peter Kassig, and Goto's friend Haruna Yukawa.
Aug 22: Shi'ite militiamen gun down 70 people in an apparent revenge attack at a Sunni mosque in Diyala province.
Sept 23: Anti-ISIS air campaign expands to Syria.
Oct 25: Mr Abadi declares first significant government victory, in the Jurf al-Sakhr area near Baghdad.
Oct 29: ISIS executes dozens of Albu Nimr tribesmen. More mass killings follow.
Nov 14: Iraqi forces recapture the strategic town of Baiji, but subsequently lose it.
Jan 25: Witnesses and Sunni leaders accuse Shi'ite militiamen of executing over 70 residents in Diyala province.
Jan 26: Staff Lieutenant-General Abdulamir al-Zaidi announces Diyala has been "liberated" from ISIS.
Feb 3: ISIS video shows Jordanian pilot Maaz al-Kassasbeh being burnt alive in a cage after his December capture in Syria.
Feb 26: ISIS releases video of militants destroying priceless ancient artefacts in a Mosul museum.
Mar 2: Iraq launches massive operation to retake Tikrit from ISIS.
Mar 5: Iraq says ISIS has begun "bulldozing" the ancient Assyrian city of Nimrud. ISIS later releases a video of militants smashing artefacts before blowing up the site.
Mar 31: Mr Abadi announces Tikrit has been retaken, a victory marred by pro-government forces burning and looting dozens of houses and shops.
Apr 5: ISIS releases video of militants destroying artefacts at the ancient city of Hatra, a Unesco world heritage site.
May 17: ISIS seizes Anbar capital Ramadi, which along with the capture of Palmyra in Syria a few days later, signal its most significant victories in almost a year.