Clashes between Iraqi troops and Sunni militants west of Baghdad have killed at least four children as the UN announced its highest level of emergency for the humanitarian crisis ignited by the advance of Islamic militants across much of the country’s north and west.

The extremist Islamic State group’s lightning advance has driven hundreds of thousands of people from their homes since June, and last week prompted the US to launch aid operations and airstrikes as the militants threatened religious minorities and the largely autonomous Kurdish region.

The UN on Wednesday declared the situation in Iraq a “Level 3 Emergency” – a development that will allow for additional assets to respond to the needs of the displaced, said UN special representative Nickolay Mladenov, pointing to the “scale and complexity of the current humanitarian catastrophe”.

The UN said it would provide increased support to the Yazidis and to 400,000 other Iraqis

The Security Council also said it was backing a newly nominated premier-designate in the hope that he can swiftly form an “inclusive government” that could counter the insurgent threat, which has plunged Iraq into its worst crisis since US troops withdrew at the end of 2011.

The UN move came after some 45,000 people, members of the Yazidi religious minority, were able to escape from a remote desert mountaintop where they had been encircled by Islamic State fighters, who view them as apostates and had vowed to kill any who did not convert to Islam.

They were able to reach safety after Kurdish fighters from neighbouring Syria opened an exit corridor. US and Iraqi forces had earlier airlifted aid to those trapped.

US officials said yesterday that roughly 4,500 people remain on Sinjar Mountain, nearly half of whom are herders who lived there before the siege and have no desire to leave.

The UN said it would provide increased support to the Yazidis and to 400,000 other Iraqis who have fled since June to the Kurdish province of Dahuk. A total of 1.5 million people have been displaced by the fighting.

The US has been carrying out airstrikes in recent days against Islamic State fighters, helping fend back their advance on Kurdish regions.

In western Iraq, fighting erupted in the militant-held city of Fallujah, about 65km west of Baghdad. The clashes on the city’s northern outskirts killed four children, along with a woman and at least 10 militants, said Fallujah hospital director Ahmed Shami.

He had no further details on the clashes, beyond saying that four other children and another woman were wounded in the violence.

It was difficult to gauge the situation in Fallujah, which has been in the hands of the Islamic State and allied militants since early January, when the insurgents seized much of the western Anbar province along with parts of the provincial capital of Ramadi.

Meanwhile, eight civilians were killed in separate attacks across Baghdad.

A bomb attached to a minibus in the central Sheik Omar area killed four commuters and wounded 11 others, a police officer said. Another bomb went off in a commercial area in the south-eastern Bayaa neighbourhood, killing two and wounding nine, another police officer said.

Two other civilians were killed and 11 wounded when two mortar rounds struck another residential area, he said. Three medical officials confirmed the casualty figures.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.