Dozens die fleeing last IS stronghold: UN

Some 90 people have died while fleeing the last stronghold of the Islamic State group in eastern Syria, two-thirds of them children under the age of 5, according to a UN agency.

The were travelling to or had recently arrived at a refugee camp in northeastern Syria, the United Nations Office for the Coordination of Humanitarian Affairs (OCHA) said.

The main causes of death were "hypothermia, pneumonia, dehydration or malnutrition complications," according to OCHA.

Between February 22 and March 1, about 15,000 people reached al-Hol camp from Baghouz, where the US-backed Kurdish-led Syrian Democratic Forces (SDF) have been battling Islamic State militants.

More than 90 per cent of the al-Hol camp's 56,000 population are women and children, according to OCHA, with some children arriving without their parents.

International agencies have called for more financial resources to meet the extensive needs at al-Hol camp.

Syria's Kurdish-led forces resumed their operation to capture Baghuz on Friday, after a lull in fighting to evacuate thousands of civilians and family members of Islamic State militants from the area.