Amman - More than 30 000 Syrian children are facing starvation in Jordan after authorities in Amman suspended life-saving food and medical aid to refugees living along its northeastern border with Syria.Up to 70 000 Syrians, mostly women and children, have been denied access to food and safe drinking water during the Islamic holy month of Ramadan, a period of fasting from dusk till dawn, after Jordanian authorities blocked emergency aid supplies to an area known as the 'berm' last month following an attack by ISIS. Shortly after the attack, Jordan declared the porous border area, which houses the sprawling Rukban refugee camp, a closed military zone", and warned that any movement in the area would be treated "without leniency", despite pleas by aid and humanitarian groups that this would put the lives of refugees at risk.At a time of year when temperatures can exceed 35°c, Al Jazeera has learned that harsh conditions in the camp have forced some Syrians to head back to Syria."We're getting terrible stories of people deciding to go back into Syria because of the appalling conditions they are facing in this desolate and remote desert area," Gerry Simpson, a senior refugee researcher and advocate at Human Rights Watch, told Al Jazeera on Friday."What these people need right now is water and food... Jordan has blocked all food and medical aid to these people - over half of whom are children. Jordan has allowed a limited amount of water, but that is nowhere near enough."The medical aid charity Doctors Without Borders warned of increasing cases of malnutrition.Of the 1 300 children under 5-years-old in the area that it screened for malnutrition, 204 were suffering from moderate malnutrition and 10 were severely malnourished.It also said that 24.7% of the children seen by medical teams had acute diarrhoea.There are an estimated 650 000 Syrian refugees registered by the UN in Jordan, and the country's northern border is the only access point through which they can enter the country."Jordan isn't the only country that is treating Syrian refugees this way," Simpson said. "Turkey has closed its border for a year and half now, and shoots at asylum seekers as they try and cross. Lebanon has severely restricted access and so Syrians aren't able to escape there either."Jordan, Lebanon and Turkey are all trapping Syrians inside this awful crucible of war. The International Community, particularly the European Union should be doing far more to reassure these counties that they are going to take in more Syrians and resettle them out of the region - thereby giving Jordan, Lebanon and Turkey no excuse but to continue to protect these vulnerable people," he added.Jordan already has a large refugee population with more than 300 000 Palestinians living in refugee camps. Many Iraqis also sought refuge in Jordan following the 2003 US-led invasion and occupation, and since the emergence of ISIS.