GENEVA (Reuters) - At least 29 children and newborns are reported to have died in a teeming camp in northeastern Syria over the past 8 weeks, mainly due to hypothermia, the World Health Organisation (WHO) said on Thursday.

About 23,000 people fleeing fighting in Deir al-Zor between Islamic State and the U.S.-backed Syrian Democratic Forces alliance, led by the Kurdish YPG militia, have arrived at al-Hol camp during the period, swelling its population, it said.

“The situation in Al-Hol camp is heartbreaking. Children are dying from hypothermia as their families flee to safety,” Elizabeth Hoff, WHO representative in Syria, said in a statement.

The United Nations agency appealed for unhindered access to the camp, saying the situation has become “critical” for 33,000 people, mainly women and children, now living there in bitterly cold winter conditions.

Many displaced had walked for days or traveled in open trucks, arriving malnourished and exhausted following “years of deprivation” living under control of Islamic State, it said.

“Thousands of new arrivals have been forced to spend several nights in the camp’s open-air reception and screening areas, without tents, blankets or heating,” the WHO added.

WHO-supported teams are working around the clock in the camp to screen new arrivals, support vaccination and refer severely malnourished children to a hospital in al-Hasakah, it said.

“Humanitarian access to the camp and surrounding roads is hampered by bureaucratic obstacles and security constraints,” it added, appealing to all parties to provide unhindered access for life-saving aid.