UN Secretary General Ban Ki-moon has raised alarm over a massive shortfall in funding for the UN aid agency assisting Palestinian refugees in the Middle East.
Ban on Wednesday urged all donors to urgently ensure adequate financing for vital services.
The UN chief said in a statement that the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) was "a pillar of stability" for Palestinian refugees.
Ban also called "on all donors to urgently ensure that the $100 million required be contributed to UNRWA at the earliest possible date so that the children of Palestine can begin their 2015-2016 school year without delay."
The agency requires USD 100 million to begin the 2015-2016 academic year in hundreds of UN-run schools for Palestinian children across the Middle East.
UNRWA has indicated that it only has funding until the end of August, when the school year is due to start in the besieged Gaza Strip, the occupied West Bank and Jordan.
The UN agency provides assistance for about five million registered Palestinian refugees in the three areas, as well as Lebanon and Syria.
The agency said it currently has enough money to maintain its services to protect public health through to the end of 2015.
According to a Ban spokesman, the UN chief has personally spoken to several world leaders in recent weeks about the unprecedented funding crisis at UNRWA.
On Wednesday, UNRWA workers held a sit-in at the agency's headquarters in the Jordanian capital, Amman, to protest against a possible decision to suspend schools for Palestinian children across the region for four months.
In late July, Palestinians in Gaza staged a protest against cuts by UNRWA to services provided to refugees there.
UNRWA recently said it was decreasing its aid to Palestinian refugees living in the Gaza Strip due to lack of funding from its international donors.
Out of the 1.8 million people living in Gaza, about 1.3 million are refugees, according to reports. Most of the refugees live in miserable conditions in eight refugee camps across the coastal enclave.