GENEVA: The United Nations on Friday urged Syria's neighbours to keep open their borders to civilians fleeing the intensifying conflict and said that the refugee exodus into Jordan was "absolutely dramatic".

More than 30,000 Syrians have arrived in Jordan's main Zaatri camp this year, including 4,400 on Thursday and another 2,000 overnight, it said. Most were fleeing fighting in the southern area of Deraa, food and fuel shortages and high prices.

Turkey has said that camps are filling up as soon as they are built and officials in Jordan said this week it would keep its borders open but wanted other countries to help it boost its ability to cope with the influx.

"It is just absolutely dramatic the inflow of people that continues into Jordan," Melissa Fleming, chief spokeswoman of the U.N. High Commissioner for Refugees (UNHCR), told a news briefing in Geneva.

Jordan now hosts more than 206,000 Syrians who have registered as refugees or await processing, while the government says that more than 300,000 Syrians are actually in the country.

A further 30,000 Syrians could be preparing to head to Jordan, according to the UNHCR's latest assessment.

Across the region, 678,540 Syrian refugees had registered or were being processed as of Tuesday, according to UNHCR figures for Jordan, Turkey, Lebanon, Iraq and North Africa.

"It is fast approaching 700,000," spokeswoman Sybella Wilkes told Reuters. "It is a challenge on every border the number of people that are arriving and crossing borders every day."

Fleming said the UNHCR commended the Jordanian, Lebanese and Turkish governments for keeping their borders open and urged them to continue to do so.

Refugees report fighting in Deraa and its suburbs but the UNHCR was not in a position to assess military activities, she said. Water and electricity are only available for intermittent periods in parts of southern Syria.

Some 25,000 to 40,000 Syrians are reported to be massed in northern Syria along Turkey's border, awaiting entry into the country which has 15 refugee camps and is building a further five, Fleming said.

"They are building camps as fast as they can and they are letting people in as soon as the camps are ready," she said.

What began as a mostly peaceful movement against President Bashar al-Assad has killed more than 60,000 people in 22 months, devastated the economy and left 2.5 million people inside the country hungry, according to the U.N.

Ted Chaiban, UNICEF director of emergency programmes who was in Syria last week, said food, basic medicines and drinkable water were getting harder to find, while families were living 20 to a room with minimal shelter and clothing in cold weather.