Christians were fleeing Iraq's city of Mosul en masse Friday after the terrorist group of ISIL relayed an ultimatum giving them a few hours to leave, the country's Chaldean patriarch and witnesses said. "Christian families are on their way to Dohuk and Arbil," in the neighboring autonomous region of Kurdistan, Patriarch Louis Sako told AFP. "For the first time in the history of Iraq, Mosul is now empty of Christians." A statement dated from last week and purportedly issued by ISIL terrorists that took over the city and large swathes of Iraq during a sweeping offensive last month warned Mosul's Christians they should convert, pay a special tax, leave or face death. "We were shocked by the distribution of a statement by the (so-called takfiri group of) Islamic State calling on Christians to convert to Islam, or to pay unspecified tribute, or to leave their city and their homes taking only their clothes and no luggage, and that their homes would then belong to the ISIL (terrorists)," Sako said. The statement, which was seen by AFP, said "there will be nothing for them but the sword" if Christians reject those conditions. The UN says over 5,500 civilians have been killed and thousands more injured in the foreign-backed militancy across Iraq so far this year. The UN mission to Iraq said in a new report on Friday that at least 5,576 civilians were killed and another 11,665 wounded in Iraq since January across the crisis-hit country. This comes as the mission has put last month’s death toll at over 2,400 across the crisis hit country. The figure also makes June the deadliest month so far in 2014. The report is the UN’s latest detailed account of the impact of months of violence by the ISIL militants in Iraq's north.