Mosul battle

Military forces have been attempting to retake the city - the last major IS stronghold in Iraq - since October.

Iraqi officials said the IS group had used laboratories in the university complex to make chemical weapons.

The head of the country's counter-terrorism operations said retaking the area was a significant victory.

"This great scientific and cultural building was liberated by the heroes," Lt Gen Talib Shaghati, said. "The liberation of the University of Mosul means much, given its cultural, social and human symbolism."

Their bodies were then hung from electricity poles in several districts, the office of the UN Human Rights Commissioner said, citing sources.

A man was also reportedly shot dead in public in central Mosul for ignoring an IS ban on using mobile phones.

Iraqi security forces are continuing their push to take Mosul back from IS.

The killings of the civilians appeared to have been carried out on the orders of self-appointed "courts", according to the UN report.

The Iraqi military has said the grave, in the grounds of an agricultural college in the town of Hamam al-Alil, contains about 100 decapitated bodies.

Most have been reduced to skeletons, so it is unclear who the victims were.

IS militants have carried out many mass killings and have been accused of fresh atrocities in the area in recent weeks.

They are being forced to retreat to Mosul, the last major IS urban stronghold in Iraq, in an offensive by pro-government forces that began on 17 October.

Hundreds of Peshmerga fighters, backed by artillery and US-led coalition air strikes, advanced on Bashiqa from three directions on Monday morning.

By late afternoon, they were moving from house to house clearing the town, a Peshmerga statement said.

Meanwhile, the Iraqi military said it had found a mass grave filled with some 100 decapitated bodies south of Mosul.

The grave was located in the grounds of an agricultural college on the outskirts of the town of Hamam al-Alil, which troops entered over the weekend.

Hundreds of Counter-Terrorism Service (CTS) troops entered Bazwaya, the last village before the city limits, after launching a dawn assault on Monday.

A BBC correspondent travelling with them says there was some resistance, with car bombs targeting the convoy.

Units of the army's ninth division are meanwhile advancing from the south.

Earlier, the military announced the start of an operation to retake the side of Mosul east of the River Tigris, which flows through the city.

They took the precaution after the wind blew smoke from the fire towards Qayyarah air field.

US Defence Secretary Ash Carter is in Baghdad on an unscheduled visit.

Meanwhile, advancing Iraqi forces entered the town of Qaraqosh, 32km (20 miles) south of Mosul, commanders say.

Qaraqosh, Iraq's largest Christian town before the war, is said to be largely empty but IS has laid landmines on the approaches to Mosul.

The militants have been attacking with suicide bombers elsewhere, driving vehicles laden with explosives at high speed towards government lines.

Bereft of one, while it may win the military battle, it will ultimately lose the strategic war.

"Make no doubt the Iraqi security forces have the momentum," Gen Gary Volesky said.

The Iraqi army has been moving towards Mosul from the south, while their Kurdish allies have been approaching from the east.

There are thought to be up to 5,000 IS fighters still in the city.

"We've seen movement out of Mosul; we've got indications that leaders have left," said Gen Volesky, giving his assessment of the situation.

But he did not specify who had fled, nor did he say where they had gone to.

Some 700,000 people are believed to remain in city, where up to 5,000 IS fighters face the third day of the operation to retake Mosul.

News that the nearby town of Qaraqosh had been liberated was later denied by a government commander.

But the US-backed coalition say they have driven IS out of 10 villages.

Government troops are moving up from the south while their Kurdish allies are approaching from the east in a two-pronged campaign which began on Monday.

But spokesman Peter Cook warned that the campaign "could take some time" as it remained to be seen whether the jihadist group would "stand and fight".

Fighting continued overnight, with IS militants attacking Iraqi army tanks.

A BBC correspondent with an army unit says the southern frontline is still some 40km (24 miles) from the city.

IS militants overran Mosul in June 2014, before taking control of much of northern and western Iraq.