A Palestinian official and an activist say local fighters in a Palestinian refugee camp in Damascus have advanced in clashes with Islamic State militants.

Damascus-based Palestinian official Khaled Abdul-Majid said Wednesday that Palestinian factions have forced the IS fighters to retreat from some positions in Yarmouk camp.

Sami Hamzawi, a Palestinian activist from the camp who currently lives outside Syria, says the Hamas-affiliated Aknaf Beit al-Maqdis group has captured several buildings and is currently advancing from areas it holds northeast of Yarmouk. Hamzawi says he is in regular contact with camp residents.

Islamic State fighters overran much of Yarmouk earlier this month, establishing a foothold in the Syrian capital for the first time.

Palestinian and Syrian officials have vowed to retake Yarmouk.