Israel has denied obstructing humanitarian aid deliveries to Gaza, after the US warned its ally in a letter to urgently boost humanitarian access or risk having some military assistance cut off. The first aid in two weeks was allowed into northern Gaza following the letter, but the UN's acting humanitarian chief Joyce Msuya described it as a "trickle". In the letter sent on Sunday, the US expressed deep concern at the humanitarian situation and said Israeli actions had contributed to it. Israel's ambassador to the UN, Danny Danon, told the Security Council that it had "flooded Gaza with as much aid as possible" and accused the Palestinian armed group Hamas of stealing and selling shipments. Ms Msuya warned that essential supplies are running out for about 400,000 Palestinians in the north, amid an Israeli ground offensive against what the military says are regrouping Hamas fighters in and around the Jabalia area. The strongly worded letter sent by the Biden administration accuses Israel of halting commercial imports to Gaza, denying or impeding nearly 90% of humanitarian movements between the north and south in September, placing excessive restrictions on dual-use goods, and instituting new vetting and customs requirements for humanitarian staff. The letter says Israel "must, starting now and within 30 days" act on a series of concrete measures to boost aid supplies, citing US laws that can prohibit military assistance to countries that impede delivery of US humanitarian aid. It says Israel must "surge all forms of humanitarian assistance throughout Gaza" before winter, including by enabling a minimum of 350 lorries a day to enter through all four major crossings and a new fifth crossing, as well as allowing the 1.7 million displaced people crowded in the coastal al-Mawasi "humanitarian area" to move inland. It also calls on Israel to ensure deliveries via the Jordanian land corridor are not impeded and to end the "isolation of northern Gaza". The Israeli government has not responded to the letter since it was leaked on Tuesday, but Danon told the UN Security Council on Wednesday that "the issue in Gaza is not a lack of aid". "More than enough aid has entered to sustain every civilian in Gaza, with over one million tonnes delivered since the war began. Yet, the challenges continue — yes, we admit that. And it's not due to Israel's efforts of failure to deliver humanitarian assistance," he said. "The real issue is Hamas. This terrorist organization has hijacked the aid, saving it for their own purposes. They steal and even sell the aid that is intended for Gazan civilians, turning humanitarian relief into a profit machine." Hamas has previously denied stealing aid and said Israel is to blame for shortages. Israel is not allowing international journalists from media organizations, including the BBC, independent access to Gaza making it difficult to verify facts on the ground. Earlier, the Israeli military body responsible for managing crossings into Gaza, Cogat, said aid had been delivered to northern Gaza for the third consecutive day following a two-week period when the UN said no aid was allowed in. Fifty lorries carrying food, water, medical supplies and shelter equipment from Jordan crossed via the Erez West crossing, it added. The UN meanwhile confirmed that almost 30 lorry loads of aid had entered the north on Monday and another 12 lorry loads the following day. Ms Msuya said that constituted a "trickle" and that "all essential supplies for survival are running out". "There is now barely any food left to distribute, and most bakeries will be forced to shut down again in the next several days without additional fuel," she said. "Given the abject conditions and intolerable suffering in north Gaza, the fact that humanitarian access is nearly non-existent is unconscionable." The US envoy, Linda Thomas-Greenfield, said the Biden administration had made it clear that "food and supplies must be surged into Gaza immediately". She also warned that a "policy of starvation" in northern Gaza would be "horrific and unacceptable". "The government of Israel has said that this is not their policy, that food and other essential supplies will not be cut off, and we will be watching to see that Israel's actions on the ground match this statement," she added. Ms Msuya also warned that the three hospitals still partially operational in and around Jabalia were facing dire shortages of fuel, blood, trauma treatment and medications. They have been overwhelmed by casualties caused by the intense Israeli bombardment and fighting on the ground between Israeli troops and Hamas fighters over the past 11 days. More than 50,000 people have fled their homes in response, but others remain stranded with water and food running out. Israel launched a campaign to destroy Hamas in response to the group's unprecedented attack on southern Israel on 7 October 2023, in which about 1,200 people were killed and 251 others were taken hostage. More than 42,400 people have been killed in Gaza since then, according to the territory's Hamas-run health ministry. — BBC