The White House not yet developed a plan to move the civilians, who are estimated to number up to 30,000, but officials have acknowledged that the creation of safe passage or an airlift might see more US troops on the ground.

On Tuesday night the president announced he had dispatched another 130 troops to Iraq to help plan for an evacuation, but he said they would not be involved in offensive operation against Islamic State of Iraq and the Levant militants who have besieged the civilians at Mount Sinjar.

“Any US military personnel anywhere in the world [have] the ability to protect themselves,” said White House deputy national security advisor Ben Rhodes told reporters at Martha’s Vineyard, where the President is holidaying, on Wednesday. “But the purpose and the mission that they are going to Iraq for is not to engage in combat.

“This is to make an assessment on a temporary basis about how we move that population off the mountain and into a safe place.”

The team is expected to report in the coming days.

“What he’s ruled out is reintroducing US forces into combat on the ground in Iraq,” Mr Rhodes said.

It is understood officials are considering both the creation of a safe land passage off the mountain or an airlift operation to rescue the Yazidi civilians who face massacre by the ISIL forces.

American aircraft have been dropping supplies to the Yazidis since Friday and bombing ISIL forces threatening the city of Erbil where another 800 or so US consulate and military staff are based. The Royal Air Force has also begun dropping supplies over Mount Sinjar.

So far the US has managed to deliver over 100,000 individual military meal packs and over 100,000 litres of water to the mountaintop.

Mr Rhodes noted that the White House had also received offers for help from Australia and France.

The United Nations has warned that the trapped civilians face genocide at the hands of ISIL.

“All possible measures must be taken urgently to avoid a mass atrocity and potential genocide within days or hours – civilians need to be protected on the ground and escorted out of situations of extreme peril,” Special Rapporteur on minority issues, Rita Izsák, said in a news release.

“We are witnessing a tragedy of huge proportions unfolding in which thousands of people are at immediate risk of death by violence or by hunger and thirst,” warned the Special Rapporteur on the human rights of internally displaced persons, Chaloka Beyani.

According to the UN many Yazidis have been told to “covernt or die” while hundreds have already been executed.

“We have reports of women being executed and unverified reports that strongly suggest that hundreds of women and children have been kidnapped – many of the teenagers have been sexually assaulted, and women have been assigned or sold to IS (ISIL) fighters as ‘malak yamiin’ or slaves,” said the Special Rapporteur on violence against women, Rashida Manjoo.

The UN estimates 250,000 minority Iraqis have been forced to flee their homes as ISIL has advanced in recent weeks.

Fawaz Gerges, head of the Middle East Centre at the London School of Economics, told Reuters the militants' spectacular brutality - the crucifixions, stoning of women and now, according to Iraqi ministers, the burying alive of women and children from the Yazidi minority - all publicised over the Internet, as "a strategic choice".