More than 30,000 Syrians have crossed into Iraq in recent days, one of the biggest such movements since the country's conflict began, the UN's refugee agency said on Monday.
Seeking refuge from brutal fighting between Kurdish forces and jihadists and a collapsing economy in their homeland, an estimated 5,000 Syrians entered Iraq's autonomous Kurdistan region just on Monday, spurring the UNHCR to mobilise vast amounts of aid in a bid to provide water and shelter.
"It appears we will be in the range of an estimated 5,000 people today," Peter Kessler, a spokesman for the UN refugee agency UNHCR told AFP, citing estimates by UNHCR staff on the border.
"That takes the estimated number to more than 30,000" since Thursday, he said.
Kessler said that while the numbers appeared to be subsiding, the UN had sent 70 trucks carrying aid for the refugees into Iraqi Kurdistan, as well as other dispatches of 2,100 tents, two prefabricated warehouses and water containers for thousands of families.
He said that initially, those who crossed on Thursday had been camped at the border for several days and were "completely exhausted, and in the most precarious position".
In more recent days, refugees appear to have been gathering in the predominantly Kurdish area of Qamishli in northeastern Syria before crossing into Iraq.
"They are frightened, they are worried, they are nervous," he said.
"They report fighting and tension in their home areas, but other people also report the collapse of the economy in the region."
The sudden influx of Syrians across the border stands in marked contrast to the relatively small numbers of refugees taken in by Iraq in recent months compared with other neighbouring countries and has forced the UN refugee agency to scramble aid to the region.
Syrian government forces pulled out of most Kurdish-majority areas of northern and northeastern Syria last year, leaving Kurdish groups to run their own affairs.
But Al-Qaeda loyalists, who have played a significant role in the rebellion against President Bashar al-Assad's regime, see the region as a vital link to fellow jihadists in Iraq and have been locked in deadly fighting with Kurdish militias in recent months.
The access of Syrian refugees to Iraq has been erratic, with political tensions and fears of a spillover of the conflict leading Kurdistan regional authorities to shut the border in May.
Some restrictions were eased last month to allow Syrians to join family members already in Iraq, but the number allowed to cross the border had remained relatively low.
All told, more than 1.9 million Syrians have fled their homeland, with most seeking a haven in Lebanon, Jordan and Turkey.
Iraq hosted nearly 155,000 registered Syrian refugees, most of them Kurds, according to the United Nations, before the latest influx.