Aid agencies working inside Syria and Iraq are baffled by a sudden, massive influx of Syrian refugees wanting to cross the northern border between the two countries.
The United Nations refugee agency says 15,000 Syrian refugees have crossed into Iraq's Kurdish region since last Thursday, with more expected to follow.
It's in marked contrast to the relatively small numbers of refugees taken in by Iraq in recent months compared to other neighbouring countries.
Kerri Worthington reports.
The vast majority of Syrian refugees pouring into Iraq's autonomous Kurdish regions in the north are women, children and the elderly.
They're apparently mostly Syrian Kurds escaping deadly clashes between Kurdish fighters and jihadists linked to al-Qaeda.
UNHCR spokesman Adrian Edwards says the sudden influx has forced the UN refugee agency to scramble aid to the region.
"Some of these Syrians have reportedly been waiting near the Tigris river for 2 or 3 days at a makeshift site UNHCR monitors at the border source scores of buses arriving on the Syrian side dropping of more people to cross over. Both these Syrian and Iraqi sides of the frontier at Peshkabour are normally tightly controlled. Most of these people are families mainly from Aleppo, Hassakeh and Qamishli."
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 and his government, see the region as a vital link to fellow jihadists in Iraq.
Jihadist forces have been locked in deadly fighting with Kurdish militias in recent months.
Stephen MacDonald, from the aid group, Save the Children, has just returned to Australia from the region.
He says the sudden influx of refugees is connected with shifts in fighting inside Syria, although precise information isn't available.
"One of the things that really concerns Save the Children and other organisations is that there are many different groups that make up the Free Syrian Army and the opposition-held areas. So we're really very, very concerned that any fighting and tension in amongst that group is going to further compound what's happening to children and their families inside Syria."
The plight of civilians prompted Iraqi Kurdistan's regional president Massud Barzani to threaten earlier this month to intervene to protect Syrian Kurds, a sign of the conflict's growing cross-border impact.
The access of Syrian refugees to Iraq has been erratic, with local 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.
The Iraqi Kurdistan foreign minister, Falah Mustafa, has told the BBC the autonomous government will do its best to deal with the influx.
"From the beginning these people have been coming, so last year, in July, we had about 10,000 Syrian refugees in the region. Today there are over 170,000. But mainly they were coing from Damascus, Aleppo and other areas that were affected by the fighting. But recenlty, in the last couple of months, some fighting has been in the Kurdish areas. That's why people want to flee. We in the Kurdistan regional government, we have welcomed these refugees. We have given them residency permits so that they ahve freedom of movement here. We have given them opportunities to find jobs and make sure that they get their living, but the numbers are increasing."
Nearly two-million Syrians are reported to have fled their homeland's 29-month-old civil war, with most seeking a haven in neighbouring Lebanon, Jordan and Turkey.
Stephen MacDonald of Save the Children says his organisation has launched an emergency response to deal with tens-of-thousands of people fleeing Syria into Iraq.
"We've rapidly scaled up our operations in northern Iraq over the last couple of days, with a view to providing food, water and basic materials for people. But the real challenge that we have across the whole region is both the Save thh Children appeal and the UN appeal are grossly underfunded and until we can get the resources that we need we're really just going to be filling gaps."
