The UN said Friday it estimates around 10,000 Palestinians have had to left homes in Gaza "due to the ongoing hostilities" amid an Israeli offensive.
"They are sheltering in schools, mosques, and other places during a global COVID-19 pandemic with limited access to water, food, hygiene, and health services," UN Office for the Coordination of Humanitarian Affairs said in a statement.
"Hospitals and access to water and sanitation services depend on electricity, the fuel for which will run out on Sunday," it added.
The office said Israeli authorities and Palestinian groups must immediately allow the UN and its humanitarian partners to bring in fuel, food, and medical supplies and to deploy humanitarian personnel.
"All parties must always adhere to international humanitarian and human rights laws," it added.
The office reiterated the UN Secretary-General Antonio Guterres's call for immediate de-escalation in Gaza and Israel.
At least 122 Palestinians, including 31 children and 20 women, have been killed, and 900 others injured in the ongoing Israeli offensive against Gaza.
Israel continues to target Gaza with heavy bombardment which caused heavy damage to residential buildings across the enclave.
To date, nine Israelis have been killed in the recent violence -- eight of them in rocket attacks in addition to a soldier killed when an anti-tank guided missile struck his jeep.
Tensions have been running high in the Sheikh Jarrah area in occupied East Jerusalem over the past month as Israeli settlers swarmed in following a court order for the eviction of Palestinian families in the area.
Palestinians protesting for the residents of Sheikh Jarrah who have been targeted and threatened with expulsion by Israeli forces.
Israel occupied East Jerusalem during the 1967 Arab-Israeli war and annexed the entire city in 1980 -- a move that has never been recognized by the international community.