JERUSALEM (AP) — Israel has imposed financial restrictions on the main U.N. agency providing aid in the Gaza Strip, a measure which prevented a shipment of food for 1.1 million Palestinians from reaching the war-battered enclave, the agency's director said Friday.

The restrictions deepened a crisis between Israel and UNRWA, whose operations have been threatened following Israeli accusations that some of its workers participated in the Oct. 7 attack that triggered Israel's war in Gaza. Those accusations have led major donor nations, including the U.S., to suspend funding to the U.N. organization and left its future in question.

UNRWA's director, Philippe Lazzarini, said Friday that that a convoy of food donated by Turkey has been sitting for weeks in the Israeli port city of Ashdod. The agency said that the Israeli contractor they work with received a call from Israeli customs authorities "ordering them not to process any UNRWA goods."

That stoppage means 1,049 shipping containers of rice, flour, chickpeas, sugar and cooking oil — enough to feed 1.1 million people for one month — are stuck, even as an estimated 25% of families in Gaza face catastrophic hunger.

The World Food Program warned Friday that Gaza could be plunged into famine as early as May. The U.N. food agency defines a famine as when 30% of children are malnourished, one-fifth of households face acute food shortages and two of every 10,000 people are dying from hunger or malnutrition.

Israel declared war and imposed a siege on Gaza in response to the Oct. 7 Hamas attack, which killed 1,200 people and took 250 others hostage. The war has led to a humanitarian crisis in Gaza, with only a trickle of humanitarian aid entering the territory each day.

Israel has long railed against UNRWA, accusing it of tolerating or even collaborating with Hamas and perpetuating the 76-year-old Palestinian refugee crisis. UNRWA, which serves about 6 million Palestinians whose families were displaced during the war surrounding Israel's creation in 1948, denies the charges. But the tensions have only intensified following the latest allegations by Israel.

Juliette Touma, communications director for the agency, said that UNWRA's bank account with Bank Leumi, which the agency has held for decades, was also frozen this week. In addition, Touma said that Israeli customs authorities notified the agency that UNRWA will no longer be granted tax exemptions.

Israel's finance minister, Bezalel Smotrich, tweeted on Thursday that "the state of Israel will not give tax benefits to terrorist aides."

Smotrich, a far-right ally of Prime Minister Benjamin Netanyahu, didn't respond to a request for comment.

The agency has been able to reroute other aid shipments through Port Said in Egypt, but Lazzarini warned Friday that the holdup means further difficulties in the already challenging task of aid distribution to Gaza. About 80% of Gaza's 2.3 million people have been displaced by the war.

UNWRA is the main provider of aid to Palestinians in Gaza, but Israeli bombardment and combat between Israel and Hamas has made much of the territory too dangerous for aid convoys to cross. For the last two weeks, the agency has been unable to deliver aid to around 300,000 Palestinians estimated to still be in the northern half of Gaza, where the World Food Program says food insecurity is the worst.

Lazzarini said efforts have instead focused on the 1.3 million displaced Palestinians sheltering in the makeshift tent camps of Rafah, a city on the border with Egypt where the agency relies on local police to escort aid convoys to distribution points and prevent theft. But that has also grown increasingly challenging, as Israeli warplanes bomb targets in the city.

Airstrikes there killed eight police officers in the city over the last four days, Lazzarini said, making police reluctant to continue helping the agency. Three strikes have taken place near an UNWRA clinic, Lazzarini said. Israeli media have portrayed the police escorts as an attempt by Hamas to seize aid shipments for its own use.

Lazzarini said that the police the agency works with weren't affiliated with militant groups. Touma said that the police escort was necessary to prevent people from throwing stones at the convoy and attempting to steal aid from them.

Israel alleged last month that 12 employees of the aid agency participated in the Oct. 7 Hamas attacks in southern Israel. Several countries suspended funding worth about $440 million, almost half of the agency's annual budget.

Two U.N. investigations are underway, including an independent review announced this week. The review, headed by a former French foreign minister, is supposed to focus on the way the agency ensures that it remains neutral and responds to allegations that it failed to do so. Colonna's team plans to look at whether the system works and how it might be improved.

Lazzarini said Friday that he immediately fired the workers, rather than suspending them, without first investigating the evidence against them. Two had been killed by the time the allegations surfaced. Lazzarini said there was too much pressure on the organization — and current conditions make investigating the workers difficult — to do anything else.

"Knowing that the organization is under fierce and ugly attacks," he said, "I could not take the risk ... I could have suspended them, but I fired them."