Starting from 2013, however, the rise of the Islamic State of Iraq and the Levant led to ethnic cleansing of the Assyrian people, including Assyrian refugees, in Iraq and Syria. This intensified following their Northern Iraq offensive in mid 2014. Most of the land that ISIS conquered in Northern Iraq was part of the Nineveh Plains, which had been the only area left in Iraq that was safe for the Assyrians. By August 2014, the Christian population of the Nineveh Plains was reduced by 60%, and almost all of the main population centers of the region were lost to ISIS.