* Young, old and vulnerable crowd tented refugee camp
* 6,000 gas heaters airlifted to Jordan to combat cold
* Aid workers say world not ready for further influx
One-year-old Ali Ghazawi, born with a heart defect, faced a battle for survival even before his family fled Syria's civil war. It was a struggle he lost two weeks ago in the bitter winter cold of a tented refugee camp in north Jordan.
Ali died two days after undergoing a heart operation in Zaatari camp, which houses at least 32,000 refugees who escaped fierce bombardment in Syria's rebellious southern province of Deraa, cradle of the uprising against President Bashar al-Assad.
"I covered my son with two blankets, but he was not warming up, and he turned blue before he passed away in my hands," said his sobbing 22-year-old mother, alone with a three-year-old daughter after she left her husband in Deraa and crossed the border in November.
Ali was the fourth baby to die in three weeks in the windswept camp. United Nations aid workers say none of the deaths were the direct result of conditions in Zaatari, yet they highlight the challenge facing relief agencies scrambling to provide basic shelter for half a million refugees in the region.
"These deaths are a result of cumulative factors, some related to shortage in needs and natural causes. But on top of that, the reality that conditions are harsh cannot be ignored," said Saba Mobaslat, programme director at Save the Children.
Jordan, Lebanon and Turkey each host more than 130,000 registered refugees, and relief workers predict the numbers will only increase as violence escalates around the capital Damascus.
Mirroring Syria's youthful population, almost 65 percent of Jordan's camp residents are newborns and young children.
"Every night we are getting children as young as four days old, six days old, one week, two weeks old, and it's a real struggle to try to make sure that everyone survives," said Andrew Harper, Jordan head of the United Nations High Commissioner for Refugees (UNHCR).
"Women are giving birth on the border, and people are coming across pregnant. It's a situation where we just need to redouble efforts, particularly as we move into winter, because you have hundreds of pregnant women who cross the border," Harper said.
Families often send the most vulnerable to safety, he added, so alongside the very young in Zaatari are many older refugees. "Last night we had a couple who were 97 years old," he said.
Along the main road in the middle of the camp's muddy and gravel streets, children of all ages race around the makeshift market place that sprang up after the camp opened in July.
Many families join in, out of enterprise or necessity, selling everything from hot falafel to household goods, old clothing and fresh vegetables.
"It's a children's camp. You walk into it and there are children everywhere. It's in your face. The male adults are staying behind, and a woman comes with 10 children without her bread earner," Mobaslat added.
In one of several UNICEF-run playgrounds, among seesaws, swings and volunteers giving music lessons, the scars of war are fresh in the minds of most children.
"I long for my home, and I hope Bashar falls to get back to my home. It's much better than here, where we are humiliated," said Mohammad Ghazawi, 12, who came to play after a break from selling cheap cigarettes.
Their elders complain that two thin blankets per refugee distributed in recent weeks were not enough to warm them in tents that let in rain water despite zinc reinforcements and waterproof layers that have helped insulate them.
"Kids are dying from cold and lack of blankets. My kids shiver at night, and one has constant diarrhoea," said Mohammad Samara, 46, who fled heavy shelling in the southern Syrian town of Busr al-Sham in October with his wife and four children.
Carsten Hansen, country director for the Norwegian Refugee Council (NRC), which has set up a heated tent that receives families on arrival, says much progress has been made to help distribute aid.
"Everybody is trying to mobilise resources ... in order to react to bigger numbers and a huge influx," Hansen said, adding that 6,000 gas heaters had been airlifted to Jordan to help heat the tent camp.
FROM CRISIS TO DISASTER?
Harper said UNHCR was working to prevent "this humanitarian crisis becoming a major disaster". But he said that while aid teams were racing to improve conditions at Zaatari, there were 100,000 other registered refugees living outside the camp and probably another 100,000 unregistered, whose living conditions were not improving.
In Lebanon, too, host to 154,000 refugees, many face a bleak winter, and aid workers expect their numbers to more than double by the middle of next year.
In the Bekaa Valley town of Bar Elias, a woman from the northern Syria province of Idlib says her home for the last year has been a wooden shack with only plastic sheeting to protect from the rain. Plastic bags are stuffed into the roof as extra insurance against leaks. "There is no water, no electricity, no school for my kids," she said in a croaky voice.
"My husband is sick. The situation is very bad."
Mads Almaas, NRC country director in Lebanon, said many more may flee Syria over the winter to escape worsening conditions there, putting even greater strain on relief efforts.
"The violence will not only continue but also get worse. And even in the increasingly likely event of the fall of Assad, we don't think the violence will end," he said.
Almaas said the United Nations would launch a regional response plan on Wednesday anticipating a total of 300,000 registered refugees in Lebanon by mid-2013. "At first we thought it was too high. Now we are concerned it is too low," he said.
In Turkey, which hosts 136,000 refugees, camps for the most part have facilities such as portable electric heaters, and refugees receive three hot meals a day from the Red Crescent. But temperatures can plunge below freezing in the rugged terrain along the 900 kilometre (560 mile) border with Syria during the winter months, and rain can be torrential and cause flooding.
Overcrowding remains a concern, with extended families cramped in single tents and ever more refugees arriving as fighting across the border drags on.
Across the region, aid workers fear an explosion in violence could leave them seriously overstretched.
"Right now funds are sufficient. What is a challenge is if we get any shocks, something like 5,000-10,000 refugees arriving (in Lebanon) in a matter of hours," Almaas said.
If fighting swept through the centre of Damascus, thousands of Syrians could flee to the Lebanese border in a matter of hours. "For that, we are not prepared as the NRC. I also question the international community's capacity."