The civilians from southern villages appear to have been forced into the city by ISIS, and witnesses said they looked to be in poor condition, with no food or accommodation.
However, it is unclear what ISIS’ intention is for these particular civilians.
The United Nations had also received reports that civilians suspected of disloyalty had been shot dead, he said.
“We are gravely worried by reports that (ISIS) is using civilians in and around Mosul as human shields as the Iraqi forces advance, keeping civilians close to their offices or places where fighters are located, which may result in civilian casualties,” Zeid said.
Displaced Iraqi families gather near Qayyarah on Friday.
“There is a grave danger that (ISIS) fighters will not only use such vulnerable people as human shields but may opt to kill them rather than see them liberated,” he said.
ISIS has used the same tactic in previous battles in Iraq, notably in Falluja in June.
Towns cleared of ISIS
Meanwhile, Iraqi security forces continue their advance on Mosul. The district of al-Shura, 25 kilometers (15.5 miles) south of the city, was emptied of ISIS fighters after an attack Saturday, army officials told CNN.
Around 35 ISIS militants were killed and six vehicles destroyed during the battle, which lasted several hours.
The army said it set up a humanitarian corridor for 250 civilians to escape to the nearby town of Qayyara.
Iraqi forces also launched an operation to cut ISIS supply lines west of Mosul, according to a statement released Saturday by Hashd al Shaabi, also known as the Popular Mobilization Units (PMUs).
The PMUs are fighting alongside the Iraqi military and Kurdish Peshmerga forces as they attempt to retake Mosul from ISIS.
Reports of executions
According to a witness, ISIS on Saturday executed about 75 Iraqi police or security officers detained after gun battles earlier this week in Mosul’s southern neighborhood of Wadi Hajar.
The men were among 600 people detained. Although ISIS released many of the civilians, the officers were taken to the southern suburb of Abu Sayf and shot near a river.
The terrorist group carried out a mass killing of 232 people Wednesday, punishing them for defying its orders, a spokeswoman for the UN human rights arm told CNN.
“ISIS executed 42 civilians in Hammam al-Alil, south of Mosul. Also Wednesday, ISIS executed 190 former Iraqi security forces for refusing to join them in the Al Ghazlani base near Mosul,” said Ravina Shamdasani of the Office of the UN High Commissioner for Human Rights.
An Iraqi man waves a white flag as his family flees the fighting Thursday. The International Organization for Migration reported Saturday that the Mosul operation has displaced 17,520 people since October 17.
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