I’ll call BS on this story because the source was the UN and they manufacture BS daily.
‘Their spirit is broken’: Iraqi forces say 1,000 ISIS fighters killed in Mosul Iraqi military estimates initially put the number of insurgents in Mosul at 5,000 to 6,000, facing a 100,000-strong coalition force. (http://www.businessinsider.com/r-iraqi-forces-say-1000-islamic-state-fighters-killed-in-mosul-2016-11)
The Iraqi Army General Command announced in November that more than 2,000 Islamic State jihadists have been killed since the start of the battle for Mosul.