Hundreds of foreigners affiliated with the Islamic State group (IS) have escaped from a camp in northern Syria amid a Turkish offensive, Kurdish officials say.
They say detainees attacked gates at the Ain Issa displacement camp as fighting raged nearby.
Turkey launched an assault last week aimed at driving Kurdish-led forces from the region.
The UN says 130,000 people have fled their homes, and the figure may rise.
Turkey accuses the Kurds of being terrorists and says it wants to force them away from a "safe zone" reaching some 30km into Syria.
It also plans to resettle more than three million Syrian refugees currently in Turkey - many of whom are not Kurds - inside the zone, which critics say could lead to ethnic cleansing of the local Kurdish population there.
President Donald Trump's decision to withdraw US troops from the area effectively triggered the Turkish incursion against the Syrian Democratic Forces (SDF) - the main Western allies in the fight against IS.
US Defence Secretary Mark Esper told CBS News on Sunday that the US was now preparing to evacuate about 1,000 troops who remained in northern Syria.
What happened at Ain Issa?
Details of the escape are still emerging - a monitoring group put the number who fled at 100, but Kurdish authorities say almost 800 relatives of foreign IS members have escaped.
Ain Issa holds about 12,000 displaced people, previously including nearly 1,000 foreign women and children with jihadist links.
It is reportedly now empty of foreign women, according to charity Save the Children, which says "foreign masked men on motorbikes are circling the camp".
BBC Arab affairs editor Sebastian Usher says it's unclear where the detainees might have gone, if their escape is confirmed.
But it gives new force to the Kurds' exasperated threat that they cannot guarantee the security of the thousands of IS suspects they hold in the face of the Turkish offensive, our correspondent adds.
"Whoever cares about the secure detention of the prisoners, they are welcome to come and find a solution," senior official Redur Xelil said, warning the Turkish operation was opening the way for IS to regroup.
The SDF says it is currently holding more than 12,000 suspected IS members in seven prisons, and at least 4,000 of them are foreign nationals. The exact locations have not been revealed, but some are reportedly close to the Turkish border.
IS has claimed recent car bombings and on Saturday declared a new campaign in Syria, which it said was to avenge its members' detention in Kurdish-run prisons.
Turkey says it will take responsibility for IS prisoners it finds during its offensive.
How is the offensive developing?
Turkish President Recep Tayyip Erdogan said on Sunday that his military forces and allied Syrian rebels had seized control of the key border town of Ras al-Ain and besieged the town of Tal Abyad, some 120km (75 miles) away.
However, SDF officials said they had pushed Turkish forces back to the outskirts of Ras al-Ain. They also reported fierce clashes around Tal Abyad, and the UK-based Syrian Observatory for Human Rights (SOHR) monitoring group said Turkey was in almost complete control there.
Both areas are key goals in the Turkish offensive against the Kurdish-led SDF forces.
There also appears to be a battle for control of a key motorway - called M4 - some 30-35km south of the border, with Turkey claiming its allied forces had already seized it.
What are the casualty figures?
They're rising, with civilians killed on both sides of the border:
- More than 50 civilians and over 100 Kurdish fighters killed in north-eastern Syria, SOHR says
- SDF says the Kurdish forces' death toll is 56 and Turkey gives a higher figure of 440
- Eighteen civilians killed in southern Turkey, according to Turkish reports
- Four Turkish soldiers and 16 pro-Turkish Syrian fighters killed in Syria, Turkey says
A female Kurdish politician and women's rights activist was among nine civilians killed on a road in northern Syria on Saturday, the SOHR said.
Hervin Khalaf, secretary general of the Future Syria Party, was ambushed and shot dead along with a driver and an aide after returning from a meeting in Hassakeh, her party said.
A spokesman for the Turkish-backed rebel group the Syrian National Army denied carrying out the killings, saying it had not advanced that far, Reuters reported.
What's the international reaction?
Pressure is building on Turkey to halt its operation.
On Saturday, France said it would suspend all weapons exports to Turkey. Germany earlier announced it was reducing its arms sales to the Nato ally.
But President Erdogan told reporters on Sunday these measures would not stop Turkey's military offensive.
"Those who think they can make Turkey turn back with these threats are gravely mistaken," he said.
The Kurds have made clear they feel betrayed by Mr Trump's withdrawal of US forces. He now says he wants the US to negotiate a truce between Turkey and the Kurds.
President Trump has suggested he would be prepared to use sanctions against Turkey if necessary.
In a tweet on Sunday, he signalled he was working on this.
Dealing with @LindseyGrahamSC and many members of Congress, including Democrats, about imposing powerful Sanctions on Turkey. Treasury is ready to go, additional legislation may be sought. There is great consensus on this. Turkey has asked that it not be done. Stay tuned!— Donald J. Trump (@realDonaldTrump) October 13, 2019