Islamic State (IS) militants have entered the Palestinian refugee camp Yarmouk in Damascus, activists and Palestinian officials say, the BBC reports.
Clashes erupted between the militants and groups inside the camp, with IS seizing control of large parts of the camp, reports said.
The UN says about 18,000 Palestinian refugees are inside the camp.
IS militants have seized large swathes of territory in eastern Syria and across northern and western Iraq.
Eyewitnesses and media reports said fighters had entered the camp from the neighbouring suburb of Hajar Aswad.
IS “now controls large parts of the camp”, the UK-based Syrian Observatory for Human Rights, a monitoring group, said.
An official with the Palestine Liberation Organisation, based in Damascus, also told AFP that “the majority of the camp” had been seized by IS.