Civilians have fled fighting in the Palestinian refugee camp Yarmouk in Damascus, officials say.
There have been heavy clashes there since Wednesday, after Islamic State (IS) gunmen attacked the district.
The UN said that nearly 100 people escaped on Sunday. A Palestinian official said that some 300 families had managed to flee on Saturday.
Up to 18,000 refugees are still trapped inside the camp as intense fighting continues around them.
Unrwa, the UN relief agency for Palestinian refugees, has called for a halt in the violence to give civilians the chance to evacuate and to allow in much needed aid.
“The lives of civilians in Yarmouk have never been more profoundly threatened,” the UN agency said in a statement.
Unrwa spokesman Chris Gunness told the BBC that the situation in Yarmouk was extremely difficult.
“We now have an intense armed conflict raging in the streets, people are cowering in their homes, too terrified to move,” he said.
Some civilians have managed to leave. Unrwa confirmed that 94 civilians, including 43 women and 20 children, had escaped and been given humanitarian support.
The Palestine Liberation Organization (PLO) in Damascus told the BBC that hundreds more had fled from this area of Damascus over the past two days.
A PLO spokesman said that two exits have been opened in the camp and that a rescue operation was being coordinated with the Syrian government and Palestinian factions inside Yarmouk.
Palestinian militiamen opposed to the Syrian government are thought to be leading the fight against IS militants in the camp, along with some Free Syrian Army fighters.
IS gunmen took over large areas of the camp on 1 April, in the group’s first major attack near the heart of the Syrian capital.
According to Reuters news agency, IS posted photos of its fighters inside Yarmouk on Sunday.
Syria’s bloody conflict, which has entered its fifth year, has claimed the lives of more than 200,000 Syrians.
The battle between forces loyal to President Bashar al-Assad, rebels opposed to his rule and jihadist militants from Islamic State has also driven more than 11 million people from their homes.
Yarmouk was first built for Palestinians fleeing a different conflict, the 1948 Arab-Israeli war.
Before the Syrian civil began, it had more than 150,000 refugees living there and had its own mosques, schools and public buildings.
But since 2012, the camp has been besieged by fighting between Syrian government troops and rebel forces.
Residents have little access to clean water, food supplies and electricity.
The few health facilities that there were in the camp have now also been engulfed in the conflict with IS.