ISIS kills hundreds in Mosul area, source says

ISIS rounded up and killed 284 men and boys as Iraqi-led coalition forces closed in on Mosul, the terror group's last stronghold in Iraq, an Iraqi intelligence source told CNN.

Those killed Thursday and Friday had been used as human shields against attacks forcing ISIS out of the southern sections of Mosul, the source said.

ISIS dumped the corpses in a mass grave at the defunct College of Agriculture in northern Mosul, the intelligence source said.

The victims -- some of the children -- were all shot, said the source, who asked for anonymity because he is not authorized to speak to the media. CNN could not independently confirm the killings.

Latest developments

• Iraqi army troops advance to storm the town of Tal Kayf.

• A large-scale offensive began early Saturday to retake Hamdaniya.

• Iraqis displaced by the Mosul offensive are seeking shelter in camps, the UN refugee agency said.

UN 'gravely worried' over human shield use

The United Nations said Friday it is "gravely worried" that ISIS has taken 550 families from villages around Mosul for human shields as Iraqi and Kurdish forces battle the terror group for control of Iraq's second-largest city.

Two hundred families from Samalia village and 350 families from Najafia were forced out Monday and taken to Mosul in what appears to be "an apparent policy by ISIS to prevent civilians escaping," Ravina Shamdasani, deputy spokeswoman for the UN Human Rights Office, told CNN.

Zeid Ra'ad Al Hussein, UN High Commissioner for Human Rights, said his office had evidence of several instances since Monday where ISIS forced civilians to leave outlying villages and head to Mosul. It also had received reports that civilians suspected of disloyalty had been shot dead.

"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," the UN official said.

"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.

His office is examining reports that ISIS shot dead at least 40 civilians in a village outside Mosul.

Any ISIS fighters who are captured or surrendered "should be held accountable in accordance with the law for any crimes they have committed," he said.

What's happening in Mosul?

Iraqi forces move on Hamdaniya

The Iraqi military launched a large offensive early Saturday to retake Hamdaniya -- also known as Qaraqosh -- from ISIS, the Iraqi Joint Operations Command center said.

The city is about 15 kilometers (nine miles) southeast of Mosul.

Iraqi troops entered the al-Askary neighborhood and liberated the mayor's building and the city's main hospital, raising the Iraqi flag over those buildings, Lt. Gen. Qassim al-Maliky said.

At least 50 ISIS militants were killed and some



of their equipment destroyed, he added.

Tal Kayf is next target

Iraqi troops are also advancing toward Tal Kayf and plan on storming the Chaldean town, the Iraqi Joint Operations Command said Saturday.

Tal Kayf is about 10 kilometers (six miles) north of Mosul.

It's the closest Iraqi security forces have come to Mosul, a CNN analysis indicates.

US defense chief pays a visit

US Secretary of Defense Ash Carter arrived Saturday in Baghdad on an unannounced visit.

Carter is expected to receive an update on the Mosul offensive and meet with Iraqi Prime Minister Haider al-Abadi before attending a troop event.

The UN refugee agency is working to establish 11 camps, five of which are already in place, to house those forced from their homes by the battle for Mosul. The camps will have capacity for about 120,000 people, the agency said.

Up to 600,000 could be helped if the refugee agency obtained sufficient funding, it said. Mosul is believed currently to have a population of about 1.5 million people, it added.

Charity Oxfam warned Saturday that more must be done to provide safe routes for those fleeing the conflict.

People who escaped from the village of Hawd, 50 kilometers (about 30 miles) south of Mosul, told Oxfam that many civilians were injured during this week's offensive.

One woman told Oxfam her children had respiratory issues after breathing in thick smoke from oil wells that ISIS militants set afire to provide cover from coalition air attacks.

Clashes in Kirkuk, Laylan

At least 40 people were killed and 76 others wounded, the majority of them security forces, in ISIS attacks on neighborhoods in Kirkuk since Friday, security sources told CNN on Saturday.

ISIS fighters targeted four police stations and Kurdish security offices Friday, spreading out through several neighborhoods. Kirkuk is 175 kilometers (109 miles) southeast of Mosul.

The media wing of ISIS, Amaq, said online that ISIS fighters had attacked Kirkuk before dawn and taken control of 10 neighborhoods as well as carried out attacks to the north and south of the city.

Previous attacks by ISIS militants on Kirkuk have been attempts either to capture the city from the Peshmerga, as the Kurdish fighters are known, or divert Kurdish troops from the fight in Mosul.

ISIS militants also tried to infiltrate Laylan, a town 20 kilometers (12 miles) east of Kirkuk, but Peshmerga forces, Kirkuk police and Shiite Turkman paramilitary forces engaged with them, killing nine of the attackers, Mohammed Wais, Laylan's mayor,

Some members of the security forces were injured during the attack, including the commander of the Turkman paramilitary forces, Wais said.

About 4,000 families are housed in four camps for internally displaced people in Laylan, said Ammar Sabah, director of the Displacement and Migration Department in Kirkuk.

The most likely reason for the attacks in Kirkuk is disruption, with ISIS demonstrating it can deploy resources far behind the front lines, CNN's Michael Holmes said near Mosul.