WASHINGTON >> The United States has sent Israel a letter warning that it will face consequences from the U.S. within 30 days if it does not allow more humanitarian aid into the Gaza Strip, the State Department spokesperson said.

Signed by Defense Secretary Lloyd Austin and Secretary of State Antony Blinken, the letter was sent Sunday to Israel’s minister of defense, Yoav Gallant, and its minister of strategic affairs, Ron Dermer, according to the State Department spokesperson, Matthew Miller.

U.S. and United Nations officials have warned in recent weeks that conditions are deteriorating further in Gaza, particularly in the territory’s north, as Israel has placed increasing restrictions on the delivery of international aid.

“What we have seen over the past few months is that the level of humanitarian assistance has not been sustained,” Miller said at a daily news briefing. “In fact, it has fallen by over 50% from where it was at its peak.”

He added that Blinken and Austin “thought it was appropriate to make clear to the government of Israel that there are changes that they need to make” to increase aid deliveries “from the very, very low levels” of the current moment. He said the level of humanitarian aid into Gaza in September was the lowest it has been at any time since the Hamas-led Oct. 7, 2023, attacks in Israel.

Miller would not specify the possible consequences if Israel did not comply, although a copy of the letter posted online by Barak Ravid, a reporter for Axios, clearly raised the possibility of suspending military aid. U.S. law bars providing military aid to any country found to be blocking the delivery of U.S.-provided humanitarian aid.

“We are now writing to underscore the U.S. government’s deep concern over the deteriorating humanitarian situation in Gaza, and seek urgent and sustained actions by your government this month to reverse this trajectory,” the copy of the letter states.

The 30-day deadline set by the letter would fall after the U.S. presidential election Nov. 5, potentially making it easier for President Joe Biden to take stronger action against Israel than he has so far been willing.

Miller said that the 30-day period was set to provide Israel with “an appropriate period of time to implement” changes to its aid delivery, rather than demanding that “this has to happen overnight.”

“It’s just a plain reading of U.S. law,” Miller said. “We are required to conduct assessments and find that recipients of U.S. military assistance do not arbitrarily deny or impede the provisioning of us humanitarian assistance. That’s just the law, and we of course will follow the law.”

He added that the letter was intended to be a private diplomatic correspondence but that the U.S. was confirming its existence after it was leaked to the media.

Blinken sent a similar letter to Gallant in April, which Miller credited with prompting Israel to increase its aid deliveries into Gaza. After that letter, he said, as many as 300 to 400 aid trucks were entering Gaza on some days — a level U.S. officials consider adequate. But, he added, Blinken also made clear at that time “that the increase couldn’t be a one-off, that it needed to be sustained.”