The UN agency runs more than 270 schools with thousands of students across Gaza Strip
Workers for the UN agency for Palestinian refugees went on strike Tuesday to protest job cuts due to a funding crisis sparked by US President Donald Trump's aid cancellation.
The agency's operations were largely paralysed in the impoverished and blockaded Palestinian enclave, where its schools, health care centres and food distribution offices play an important role.
UNRWA, as the agency is known, runs more than 270 schools with some 280,000 students in the strip, where Islamist movement Hamas is in power.
The strike that follows more than 250 job cuts in Gaza and the occupied West Bank is to continue on Wednesday.
More than 500 full-time roles have also become part-time.
Even before the strike, laid-off employees had been preventing international and local staff from accessing UNRWA's headquarters in Gaza City.
On Monday, the agency pulled part of its international staff out of the Gaza Strip due to security concerns, it said.
A source with knowledge of the situation said six foreign staffers remained out of the 19 who are usually present.
Amir al-Mashal, head of the UNRWA employees union in Gaza, pledged "an intensification of union actions" in the coming weeks.
Adnan Abu Hasna, an UNRWA spokesman in Gaza, called on the union to "return to the negotiating table immediately."
A Hamas official said on condition of anonymity on Tuesday that "no harm has been done to any Arab or foreign staff," while adding that the Islamist movement supports the employees' demands.
"The agency's crisis has been invented for political reasons," he said. "No one can take way refugees' right of return."
The United States has traditionally been UNRWA's largest contributor, providing around $350 million (300 million euros) a year, but Trump has cancelled all support.
His administration, as well as Israel, opposes how the agency operates and how the number of refugees is calculated.
Palestinian leaders accuse the White House of blatant bias in favour of Israel and of adopting the Israeli government's positions.
More than 750,000 Palestinians fled or were expelled during the 1948 war surrounding Israel's creation.
They and all their descendants are deemed by the UN agency to be refugees who fall under its remit.
Created in 1949, UNRWA supplies aid to more than three million of the five million eligible Palestinian refugees in Jordan, Lebanon, Syria and the Palestinian territories.
Around 13,000 people work for UNRWA in Gaza, where more than two-thirds of the roughly two million residents are eligible for aid.
Israel and Palestinian militants in Gaza have fought three wars since 2008.