At a UN Security Council meeting on Wednesday, Israel’s UN ambassador Danny Danon declared that Fletcher and OCHA were no longer neutral and that hundreds of OCHA employees would undergo security vetting. Israel would also restrict OCHA visas to one month, he said.

“Israel has uncovered clear evidence of Hamas affiliation within OCHA’s ranks,” Danon told the 15-member council without providing evidence.

In a letter to the security council on Thursday, Fletcher said Danon’s remarks were the first time any such concern had been raised and that the accusations were “extremely serious and have security implications for our staff”.

“I expect the Israeli authorities to immediately share any evidence that led them to make such claims to the council,” Fletcher said.

He noted that around the world, OCHA engages with all parties to armed conflict to secure humanitarian access, press for the protection of civilians and promote respect for humanitarian principles, adding, “As Israeli authorities know, our contacts with Hamas have also supported hostage releases.”

Israel is committed to helping civilians and getting aid to those in need, Danon said, though he warned, “We will not work with organisations that have chosen politics over principles.”

The war in Gaza was triggered on Oct 7, 2023, when Hamas killed 1,200 people in southern Israel and took some 250 hostages, according to Israeli tallies. Since then, Israel’s military campaign has killed nearly 60,000 Palestinians, according to Gaza health authorities, and reduced much of the enclave to ruins.

“We must hold all parties to the standards of international law in this conflict,” Fletcher wrote in his letter. “We do not choose between demanding the end to the starvation of civilians in Gaza and demanding the unconditional release of all the hostages.”

Israel, which controls all supplies entering Gaza, denies it is responsible for shortages of food.