At least 232 people have been slaughtered and tens of thousands taken hostage by Islamic State group militants in Mosul, the UN rights office said on Friday.
The civilians were massacred by the extremist fighters in the besieged Iraqi city, as anti-IS forces step up the battle to oust the group from the northern city.
"On Wednesday 232 civilians were reportedly shot to death. Of these there were 190 former Iraqi security forces officers," rights office spokeswoman Ravina Shamdasani told reporters in Geneva.
"These reports have been corroborated to the extent possible," she added.
The number of people killed in recent days could be higher, she suggested.
Militants have been forcing families out by gunpoint, or killed those who resist.
At least 5,370 families were abducted by IS from Shura sub-district, another 160 families from al-Qayyarah sub-district, 150 families from Hamam al-Ali and 2,210 families from Nimrud.
These people are being moved to strategic IS positions, where it is feared they will be used as human shields.
Shamdasani added that 60,000 people are currently in Hamam al-Alil, which previously had a population of 23,000.
"We very much fear that these will not be the last such reports we receive of such barbaric acts by IS," said rights office spokesman Rupert Colville.
Baghdad and Kurdish forces, joined by a US-led coalition of 63 countries, are in the second week of a major operation to retake IS' last stronghold in Iraq.