The UN refugee agency says thousands of Syrian refugees have been crossing into Iraq's Kurdish region.
The United Nations High Commissioner for Refugees (UNHCR) says that up to 30,000 refugees have entered northern Iraq since August 15.
Youssef Mahmoud, a spokesman for the UNHCR in Iraq's Kurdish region, said that number was reached when an additional 3,000 refugees made the crossing on August 19.
The outflow of people, many of them Syrian Kurds, comes as fighting intensifies between Islamist groups and Kurdish militias in northeastern Syria.
"The situation is very tough. There is the [rebel Syrian] Free Army, some Kurds, the Al-Nusra Front, who, as we have heard, are looking for Kurds to kill and behead," refugee Fuad Ahmed told RFE/RL's correspondent in Duhok.
"Why? Why are they against the Kurds? We couldn't sleep yesterday because of the shelling."
The Al-Qaeda-linked Al-Nusra Front reportedly accuses Syria's Kurds of abandoning the Syrian revolution against the regime of Bashar al-Assad.
That charge comes as Islamist groups seeking to establish their own areas of control in the Syrian Kurdish region battle Kurdish militias trying to expel them. Syrian Kurd leaders said last month they planned to set up their own interim administration until the civil war in Syria is over.
Other refugees said they fled fighting in their home areas so quickly that they brought nothing with them.
"The situation is very bad. There is no work, no electricity, no water, no bread. There was shelling and bombing in Al-Hasakah yesterday until the early morning. It is chaos," refugee Rania Nadir told RFE/RL in Irbil.
"We couldn't bring anything with us, we just fled with our children."
The refugees have been able to pour into Iraq in recent days by taking advantage of a new pontoon bridge along the largely closed Iraqi border.
There are already some 154,000 Syrian refugees registered in Iraq.
The UNHCR says nearly 2 million Syrians have fled their homeland during the 29-month-long conflict, most seeking safe havens mostly in Jordan, Turkey, and Lebanon.
With reporting by AFP and Reuters