Six people have been killed and another 13 wounded in fighting in Lebanon's Ein el-Hilweh refugee camp, the Palestinian Red Crescent reported.
The latest clashes between Palestinian factions in the camp have brought the death toll up to 15 people since Thursday.
Fights flared up last week when the Fatah group and allies attacked suspects accused of killing a senior Fatah member.
Lebanon's General Security agency announced a cease-fire on Monday. Senior Palestinian officials, including leaders of Fatah and Hamas expressed their "full commitment to consolidating the ceasefire."
Fights flared up again on Wednesday after a previously negotiated cease-fire collapsed.
The UN agency that deals with Palestinian refugees, UNRWA, said that the fighting has displaced hundreds of families.
Fighting in Lebanon's Ein el-Hilweh camp has displaced hundreds of Palestinian families, according to the UN Deutsche Welle
What is the Ein el-Hilweh camp?
Ein el-Hilweh is located near the coastal city of Sidon, and hosts some 50,000 Palestinian refugees. Members of the Palestinian Fatah group, which is the dominant force in the occupied West Bank, and rival Islamist militant groups have been struggling for control in the camp for decades.
The camp, which is Lebanon's largest, was created for Palestinians who fled or were forced from their homes during the 1948 Arab-Israeli War, an
event known by Palestinians as the "Nakba," or catastrophe.
The Lebanese army is barred from entering Lebanon's 12 Palestinian refugee camps per the Egyptian-brokered 1969 Cairo Agreement.
This leaves Palestinian groups to handle security among themselves, with rivalry among factions frequently leading to outbreaks of violence.