MOSUL, IRAQ: Islamic State fighters have reportedly massacred scores of people around its Iraq stronghold of Mosul in the past week, U.N. human rights spokesman Rupert Colville said on Tuesday, citing preliminary information from sources in the area.

On Sunday, IS reportedly killed 50 former police officers being held in a building outside Mosul, and last Thursday Iraqi security forces discovered the bodies of 70 civilians in houses in Tuloul Naser village south of Mosul, Colville said.

"The bodies had bullet wounds, but it is not known for sure at this point who was responsible for the killings," he said.

In Safina village, about 45 km (30 miles) south of Mosul, 15 civilians were killed and their bodies thrown into the river in an attempt to spread fear, and six men, apparently relatives of a tribal leader fighting against IS, were tied to a vehicle and dragged around the village.

"The six men were also allegedly beaten with sticks and gun butts. It is not clear what happened to them subsequently," he said.

IS fighters had also reportedly shot dead three women and three girls and wounded four other children, allegedly because they were trailing 100 meters (330 ft) behind during a forced relocation from Rufeila village.

"The victims were lagging behind because one of the children had a disability. She was apparently amongst those shot and killed," Colville said.

The sources of the information included civilians and established sources in northern Iraq that the U.N. had used in the past.

"It’s a mix of sources, and obviously some of them we can’t even come close to identifying, or even the locations, for protection reasons, particularly for those in areas that are still held by ISIL, and in other cases there’s a major battle (going on)."

Some reports came from Iraqi government sources but also needed verification, he said.

In additon, Reuters reports: U.N. concerned about 'collective punishment' of Arabs in Kirkuk

The United Nations voiced concern on Tuesday that Kurdish authorities had forced 250 displaced Sunni Arab families to leave Kirkuk after an Islamic State attack on the Kurdish-controlled city, calling the move "collective punishment".

Lise Grande, the UN humanitarian coordinator for Iraq, told Reuters in an interview that the action came days before an expected mass exodus from the northern Sunni city of Mosul, where an offensive by Iraqi forces, backed by a U.S.-led coalition, is underway against Islamic State.

"We were informed that two days after the attack by ISIL or Daesh, the Kirkuk authorities announced that they will be expelling the (displaced Sunni Arab) civilian population and just a few hours after the announcement we understand that around 250 civilian families felt they had no choice but to leave," Grande said.

"The United Nations is very concerned about any action that could be understood as collective punishment," she said, adding that she was worried that the move could set a precedent.

Kirkuk is the most disputed area of Iraq because of its complex population mix. The Kurds took full control of the province in 2014 after Islamic State overran much of the north of the country, and Arabs complain that Kurds have since flooded to Kirkuk to tilt the demographic balance.

"Those who are displaced have the right to decide when they return and where they are going to live. They cannot be expelled this is why we are so worried of this particular precedent," Grande said.

Grande said the displaced people left towards the nearby provinces of Salahuddin, Anbar and Diyala.

Authorities in Kirkuk suspect the Islamic State fighters who attacked Kirkuk on Friday were helped by Sunni sleeper cells. Grande said the United Nations had no evidence that the families had helped Islamic State but the timing of the move suggested it was used as a pretext to force them out.