Over the next 30 days, Blinken and Austin said Israel must allow 350 aid trucks a day into Gaza. The UN World Food Programme (WFP) said none have entered the strip in October so far and most aid organisations estimate that around 700 trucks a day are needed to meet basic survival needs.

The language in the letter suggests a tougher line than Washington has previously taken, although White House National Security Communications Advisor John Kirby insisted in a call with journalists on Tuesday that “the letter was not meant as a threat”. Kirby also added that it simply reiterated a position the administration had communicated to Israel in the past.

“From a humanitarian perspective, a 30-day deadline is basically a death sentence, especially for those in northern Gaza that are facing famine,” Natasha Hall, a senior fellow at the Center for Strategic and International Studies (CSIS), told Middle East Eye.

With three weeks remaining until the US presidential election, Miller pushed back against suggestions that the timing of the letter was designed to shift attention to the new president-elect by the time the deadline arrives.

The US has spent much of the past year taking credit for what Palestinians say is highly inadequate aid reaching Gaza. The Biden administration attempted to build a humanitarian pier for goods off Gaza’s coast, but it failed and was dismantled due to weather conditions. It also tried airdrops, which proved deadly as recipients had to wade into deep water to retrieve the packages.