The UN agency for Palestinian refugees (UNRWA) has been a lifeline for millions of Palestinians since it was set up nearly 70 years ago.
On Friday, the United States, by far the biggest contributor to the agency, announced it was halting its funding to the organisation, which it labelled "irredeemably flawed".
- Key funder -
The United Nations Relief and Work Agency (UNRWA) was established in December 1949 by the UN General Assembly after the 1948 war surrounding Israel's creation.
More than 760,000 Palestinians either fled advancing Jewish troops or were forced from their homes, mostly towards neighbouring countries.
UNRWA became by default the only guarantor of the international status of those displaced as Palestinian refugees.
It provides aid to more than three million out of the five million Palestinians registered as refugees, through its schools and health centres in Palestinian territories, but also in Lebanon, Jordan and Syria.
There are 58 refugee camps recognised by the agency, of which 19 are in the West Bank, a Palestinian territory under Israeli military occupation for over half a century.
UNRWA schools provide an education to more than 520,000 children, taking 54 percent of the agency's budget. The agency also provides healthcare and financial support.
It employs more than 20,000 people in the Middle East, mostly Palestinians.
- End of US financing -
The United States was the largest single donor to UNRWA, providing more than $350 million (300 million euros) in 2017.
The next largest funder, the European Union, donated half that figure.
In January 2018, Washington donated only $60 million to the agency.
On Friday, President Donald Trump's administration said "the United States will not make additional contributions to UNRWA".
Israel, which welcomed the US decision, accuses the organisation of perpetuating the Middle East conflict by maintaining the idea that millions of Palestinians are refugees with a right to return to the homes from which they or their ancestors fled or were expelled.
On Thursday, UNRWA's commissioner general Pierre Kraehenbuehl said the agency has a crucial role until a final resolution to the Israeli-Palestinian conflict is found.
Palestinians point out that the United States gives $3 billion in military aid every year to Israel.
America's termination of funding was described as "cruel and irresponsible" by senior Palestinian official Hanan Ashrawi.
- 'Very serious repercussions' -
UNRWA already faced desperate and chronic financial shortages before Trump's announcement.
The agency is almost completely financed by voluntary contributions by United Nations member states.
In 2015, the agency nearly closed all its schools due to shortfalls, and the organisation carried over a deficit of tens of millions of dollars last year.
On August 30, Jordan announced the organisation of a conference on September 27 in New York to support the agency, which needs at least $200 million by the end of the year.
Germany has announced a "substantial" increase to its contribution.
Mahmoud Mubarak, director of the community-run committees that run the 19 refugee camps in the occupied West Bank which accommodate some 500,000 Palestinians, warned of the "very serious repercussions" of the US move.
By the end of September, "UNRWA won't have a penny," the agency's spokesman Chris Gunness warned in late August.