At least 12 children have died in freezing temperatures and harsh living conditions in a displacement camp in Syria on the border with Jordan, the UN said on Wednesday.
Some of the dead infants in Rukban had not made it past their first week of life, the UN agency Unicef said.
“Despite repeated warnings, the deaths of children in Rukban continue to increase at an alarming rate. Since the beginning of the year, one child has died every five days,” Geert Cappelaere, Unicef regional director for the Middle East and North Africa, said.
Near 80 per cent of the camp’s estimated population of 45,000 are women and children.
“The first hours, days and months of life are the most critical for an infant’s survival. How many more warnings will it take to prevent children from dying? There is no more time to waste,” Mr Cappelaere said.
The camp remains the most desperate settlement in the war-torn country. Residents say conditions, especially during the winter, are unbearable due to harsh environments.
Aid organisations and the UN have had limited access to Rukban, situated in the berm between Jordan and Syria.
The last time aid was delivered to the area was earlier this month.
A convoy of 133 trucks sent by the UN and Syrian Arab Red Crescent transported aid, including food and clothes, to camp residents.
It also included healthcare items and medical supplies to immunise women and children. Residents lamented the aid was not enough to meet the camp's demand.
“Despite the best efforts of the humanitarian community to provide emergency support, the desperate conditions in Rukban are simply no place for a child to be born or to grow up,” Mr Cappelaere said.
Residents of the camp have been forced from their homes in Palmyra and Homs by the war. Many fled President Bashar Al Assad’s regime and ISIS.
Mr Cappelaere called on all parties to consider children first and urgently find durable solutions.
This comes as Russian officials said they are preparing to evacuate the camp along with the Syrian government next week.
Rukban is situated inside the so-called demilitarised zone set up by US forces, but Damascus claims US troops are occupying the Syrian territory and providing a safe haven for rebels.
The zone is meant to shield US troops at the Al Tanf military base, near the Jordan-Syria border.
Both Moscow and Damascus blame Washington of failing to provide adequate living conditions inside the camp.
On Wednesday, Save the Children said that infants displaced from ISIS-held areas in Syria have shown signs of psychological distress.
The British charity said that children were "likely to have witnessed acts of brutality and lived under intense bombardment and deprivation in the last enclave held by the group".
"Many will likely need long-term mental health and psycho-social support to recover from their experiences."
Children aged between 10 and 14 years are showing signs of nervousness, withdrawal, aggression, nightmares and bed-wetting, the charity said.
It observed children at the Al Hol camp as US-backed forces battle ISIS in the last scrap of territory it holds in the village of Baghouz.