The Biden administration sharply intensified pressure on Israel this week to improve dire conditions for civilians in the Gaza Strip, warning that it would be forced to take punitive measures, potentially including a suspension of military aid, if the flow of humanitarian assistance is not increased within a month.

In an Oct. 13 letter to senior Israeli officials, Secretary of State Antony Blinken and Defense Secretary Lloyd Austin demanded urgent steps to ensure that noncombatants have access to food and other necessities, blaming lawlessness and actions by the Israeli government in permitting a deterioration of conditions in Gaza, according to two officials, who spoke on the condition of anonymity to discuss correspondence that had not been made public.

Absent a change, Blinken and Austin cautioned, the administration would be obliged to take steps laid out under policies linking compliance with international norms to the provision of U.S. weapons and military assistance. The letter gives Netanyahu one month to comply, which would delay any action until after the U.S. presidential election.

The warning from Austin and Blinken, addressed to Israeli Defense Minister Yoav Gallant and Minister for Strategic Affairs Ron Dermer, raises the possibility that the United States could suspend arms transfers to Israel if the government of Prime Minister Benjamin Netanyahu continues to block the flow of humanitarian aid, which the United Nations recently said has not reached Gaza in two weeks.

U.S. officials say they are concerned about the sharp drop-off in aid, which they say could make the provision of military aid illegal under U.S. law. But critics say there have been ongoing humanitarian problems with little change in U.S. policy.

President Joe Biden made clear his displeasure with the Israeli restrictions on aid to northern Gaza when he spoke by phone to Netanyahu last week, noting “the imperative to restore access to the north, including by reinvigorating the corridor from Jordan immediately,” according to a readout of the call.

The Israeli military office that oversees aid distribution in Gaza, COGAT, has denied that Israel halted the “entry or coordination of humanitarian aid” in northern Gaza.

U.S. officials believe that giving Israel 30 days to comply with the demands — vs. forcing a faster schedule — is reasonable, given the complexity of the response required and the schedule of U.S. weapons deliveries.

Critics of Biden’s handling of the conflict between Israel and Hamas, the Iranian-backed militant group whose fighters attacked the country on Oct. 7, 2023, have blamed his administration for failing to leverage Washington’s extensive transfer of arms that Israel has used in Gaza. More than 40,000 people have died in the past year of conflict, according to local health authorities.

Since the war began, the administration has halted only one shipment of U.S. weapons bound for Israel. In May, Biden decided to continue the flow of arms after his administration issued a 46-page report on Israel’s compliance with humanitarian laws, a review requested by Democrats in Congress alarmed by the war’s mounting civilian toll. The report found that Israeli “action or inaction” had contributed “significantly” to the insufficient flow of aid to Palestinian civilians, but it also said that the United States does not “currently assess that the Israeli government is prohibiting or otherwise restricting the transport or delivery of U.S. humanitarian assistance.”

That claim was rejected by the vast majority of aid and development organizations working to assist Gazans, including Oxfam International, which accused the administration of “turning a blind eye” to Israel’s “clear” obstruction of aid.