No combat troops to Iraq: Obama

He has asked his national security team to prepare other options to support Iraqi security forces.

Obama also made clear in his remarks that the current situation "is not solely or even primarily a military challenge."

"Over the past decade, American troops have made extraordinary sacrifices to give Iraqis an opportunity to claim their own future.  Unfortunately, Iraq’s leaders have been unable to overcome too often the mistrust and sectarian differences that have long been simmering there, and that’s created vulnerabilities within the Iraqi government as well as their security forces," he said.

"So any action that we may take to provide assistance to Iraqi security forces has to be joined by a serious and sincere effort by Iraq’s leaders to set aside sectarian differences, to promote stability, and account for the legitimate interests of all of Iraq’s communities, and to continue to build the capacity of an effective security force.  We can’t do it for them.  And in the absence of this type of political effort, short-term military action, including any assistance we might provide, won’t succeed," je said.

The US president said, "Iraq's leaders have to demonstrate a willingness to make hard decisions and compromises on behalf of the Iraqi people in order to bring the country together."

He concluded his statement by reiterating that the United States' top priority is to continue "being vigilant against any threats to our personnel serving overseas," adding that the administration will consult closely with Congress about appropriate action going forward, and keep Americans fully informed on the next steps in this situation.

Earlier, the United Nations human rights chief expressed “extreme alarm” on Friday at reports of summary executions and extrajudicial killings, and the massive displacement of some half a million people, many of whom are now in urgent need of shelter.

“The full extent of civilian casualties is not yet known,” UN High Commissioner for Human Rights Navi Pillay said, “but reports suggest the number of people killed in recent days may run into the hundreds, and the number of wounded is said to be approaching 1,000.”

Pillay added that she was deeply disturbed by reports that fighters from the groups, Islamic State of Iraq and the Levant (ISIL, also known as ISIS), and prisoners they had released from jails in Mosul and provided with arms “have been actively seeking out – and in some cases killing –soldiers, police and others, including civilians, whom they perceive as being associated with the Government.”

Under these circumstances, she said, “murder of all kinds, mutilation, cruel treatment and torture constitute war crimes”. She warned that ISIL would be under “particular scrutiny” given their “well-documented record of committing grave international crimes in Syria.”

In March, the Commission of Inquiry on Syria accused ISIL of committing crimes against humanity, in addition to other gross human rights violations, in the Syrian provinces of Raqqa, Idlib and Aleppo.

More recently, OHCHR received reports of the summary executions of Iraqi army soldiers during the capture of Mosul, and of 17 civilians on one particular street in Mosul City on 11 June.

Addressing everyone fighting in the conflict, the top UN human rights official urged that all feasible precautions be taken to spare civilians from the effects of hostilities, and to respect, protect and meet the basic needs of civilian populations.

“I am extremely concerned about the acute vulnerability of civilians caught in the cross-fire, or targeted in direct attacks by armed groups, or trapped in areas under the control of ISIL and their allies,” Pillay said. “And I am especially concerned about the risk to vulnerable groups, minorities, women and children.”

She also said humanitarian access and the safety of aid workers are a “prominent concern given the unpredictable nature of ISIL, and the manner in which it creates insecure and volatile environments, which hinder access and the delivery of humanitarian assistance.”

Local authorities said 300,000 people have sought shelter in the Erbil and Duhok governorates of Iraq’s Kurdistan region, many arriving with little more than the clothes they are wearing.

The UN refugee agency (UNHCR) reported today that a shortage of shelter is a key challenge for many of the hundreds of thousands of people who fled.

“Many people have no money and nowhere to go,” UNHCR said in a news release. The UN agency is working with the government and other partners to pitch tents and provide relief items such as plastic sheets and hygiene kits.

UNHCR spokesperson Adrian Edwards said the rate of new arrivals to the Kurdistan region has slowed over the last day or so, but “the situation remains fluid with fighting continuing on several fronts and further displacement could take place.”