David Cameron and Barack Obama have pledged to work together to avoid "genocide" in Iraq amid a growing threat from Islamic State (IS) extremists.
The Prime Minister and US President discussed the air drops of drinking water and other essential supplies being carried out by both countries around the Sinjar mountains, where thousands of people from the Yazidi minority religious group have been trapped.
But in a telephone call this evening, the leaders admitted that a "long term solution" would be needed to quell the IS advance.
A Downing Street spokesman said: " The Prime Minister welcomed the US efforts and made clear that we are keen to work with the Americans on the humanitarian effort.
"They agreed that the immediate priority is to get vital supplies to those trapped on Mt Sinjar and the UK will join the US in delivering aid drops.
"Both leaders also agreed that aid drops are not a long term solution, and that a way must be found to get these people to safety and to avert a genocide.
"They agreed that UK and US officials should work together, along with international partners, to find a way forward. They also agreed on the need for the Iraqis to establish an inclusive government as swiftly as possible to unite all Iraqi communities against (IS) terrorists."
The US has begun airstrikes against IS targets engaging Kurdish forces near the key city of Irbil, but Britain has ruled out military action at this stage.
Instead the Government has announced an £8 million emergency package of humanitarian aid, including reusable filtration containers, tents, and solar lights which can also recharge mobile phones.
Some £3 million will go to charities and NGOs already on the ground and helping displaced people in northern Iraq, and £2.5 million to the International Committee of the Red Cross.
A further £500,000 will be used to ensure Kurdish and UN systems can co-ordinate properly.
Two C130s are now en route to the troubled country from RAF Brize Norton.
Speaking after chairing a meeting of the Government's Cobra committee today, Foreign Secretary Philip Hammond said: "We can expect a continuing drumbeat of airdrop operations working in co-ordination with the US and potentially with others as well.
"But more widely we are looking at how to support this group of people and get them off that mountain, how we are going to facilitate their exit from what is a completely unacceptable situation."