GENEVA (Reuters) - Up to 700,000 Syrian refugees may flee abroad by the end of the year, the U.N. refugee agency said on Thursday, almost four times its previous forecast for the exodus from the deepening crisis.
About 294,000 refugees fleeing 18 months of conflict in Syria have already crossed into four neighboring countries - Jordan, Iraq, Lebanon and Turkey - or await registration there, it said.
"This is a significant outflow taking place, 100,000 people in August, 60,000 in September and at the moment 2,000 or 3,000 per day or night," Panos Moumtzis, regional refugee coordinator for the U.N. refugee agency UNHCR, told a news briefing.
"For example, Zaaatri camp, which is a town, did not exist until 30 days ago, it was a piece of desert basically," he said.
The UNHCR's previous forecast - of 185,000 refugees - was surpassed in August. It had been made in June.
The uprising against President Bashar al-Assad, which erupted in March last year, has become an armed insurgency in which activists say 30,000 people have been killed.
Bombardment and heavier fighting between government forces and militants is forcing Syrians to flee hot spots across the country, Moumtzis said. Many cross borders with only the clothes on their backs after a perilous journey through frontlines.
"These are families, women and children who escaped Homs, Hama, Deraa, Idlib, Aleppo who have come out with traumatic experiences and have told us they have fled," Moumtzis said.
"We have been overwhelmed with catching up basically, because every week we have another 15,000 to 20,000 who have arrived."
Other Syrians, who fled the uprising early on, now find they have depleted their resources and are registering as refugees.
U.N. aid agencies and humanitarian partners issued a funding appeal of $487.9 million to try to meet growing needs before a bitter winter sets in.
They are struggling to provide winterized tents, caravans, blankets, clothing, and food for up to 700,000 refugees expected to be staying in camps or as guests in host communities.
Turkey, which currently hosts 87,774 refugees in 13 camps is building three more camps, while most of the 94,716 refugees in Jordan are staying with host families, apart from 31,000 housed at the Za'atri camp.
Lebanon does not have any camps but is hosting 78,452. Most of the 33,063 in Iraq are in a single camp in the north.
"We are running against time with winter coming," said Edward Kallon of the World Food Programme (WFP), the U.N. agency which aims to provide hot meals or other rations to nearly 200,000 Syrian refugees this month and roughly double that by year-end.
Women and children make up about 75 percent of the refugee population, and education and health care are priorities.
"Over half of the refugee population are under 18 and a fifth are under five and these are always the most vulnerable," said Dermot Carty, Deputy Director of Emergency Programmes at the U.N. Children's Fund (UNICEF).
"Schooling continues to be a problem," he said.
About 5,000-6,000 Syrians have reached other parts of north Africa, mainly Egypt, while some 15,000 refugees have turned up in Europe, including in Cyprus and Greece, according to the UNHCR.
The agency forecast that Jordan could host 250,000 by the end of the year, Lebanon 120,000, Turkey 280,000 and Iraq 60,000.
Moumtzis paid tribute to Syria's neighbours for keeping their borders open but said donors needed to share the financial burden of caring for the refugees.
"The most important thing for all of us is to make sure they are in a safe place," he said.
Reporting by Stephanie Nebehay; Editing by Andrew Osborn