THE United Nations has warned of “catastrophic humanitarian fallout” if the Syrian government offensive to capture the last rebel-held area of Idlib continues.

Aid agencies are reporting that thousands of people have been forced to flee their homes, and that children have been left to sleep in the open in fields. The widespread destruction of hospitals has left millions without medical help.

At least 225,000 civilians have fled their homes as the military offensive, which began late last month, pushes ahead. There were unconfirmed reports from aid agencies that five children had died in air strikes this week; this makes a total of 38 children and more than 150 civilians dead since the renewed offensive began.

Eighteen hospitals have been targeted, and attacks on medical facilities have been occurring at a rate of one a day since the fighting began. Three camps for internally displaced people have also been struck, and 17 schools have been forced to close.

Idlib is the last area held by rebels. It has been subject to a truce brokered last year by Russia, which backs President Bashar al-Assad, and Turkey, which supports the opposition. The truce set up a buffer zone separating the two sides, but the takeover of the area by the jihadist militant group Hayat Tahrir al-Sham has led to an escalation of violence in recent weeks.

The United States government said on Tuesday that it suspected the Syrian government of continuing to use chemical weapons, citing a possible chlorine attack on 19 May. The State Department warned that the use of such weapons would lead it to “respond quickly and appropriately”. Last year, President Trump and European allies carried out limited air strikes from warships in retaliation for a chemical weapons attack near Damascus which killed at least 40 people.

World Vision is working through partners in the area to support the humanitarian response, although some other NGOs have suspended operations owing to the escalation of violence. The charity’s director of Syria Policy and Advocacy, Caroline Anning, said: “Almost a quarter of a million people have been forced to flee their homes since the end of April, often with only what they can carry.

“Conditions are desperate in the areas where they are arriving, which are already overwhelmed with displaced families from elsewhere: children are sleeping outdoors in open fields, and there is a lack of shelter, clean water, food, and health care. In the areas where there has been heavy fighting, dozens of communities are reported to have been completely abandoned.

“We know that at least 45 health facilities have been forced to close in frontline areas, depriving tens of thousands of people of vital care. This will have potentially deadly consequences for the sick, injured, and women going into labour.”

NGOs are calling on the UK and other countries on the UN Security Council to exert pressure on both sides, and on their supporters, to protect the region’s three million civilians, approximately one million of whom are children.