WASHINGTON/GAZA - The Joe Biden administration confirmed Tuesday that US secretaries of state and defense co-signed a letter Sunday that was sent to their Israeli counterparts, urging Israel to improve the humanitarian situation in Gaza within the next 30 days.

During a press briefing on Tuesday, State Department spokesperson Matthew Miller confirmed to reporters the letter co-signed by Secretary of State Antony Blinken and Secretary of Defense Lloyd Austin that was addressed to Israeli Minister of Defense Yoav Gallant and Minister of Strategic Affairs Ron Dermer.

The letter was intended "to make clear our concerns the levels of humanitarian assistance that have been making it into Gaza," Miller said, adding that the United States considers the letter "to be a private diplomatic communication that we did not intend to make public from our side."

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According to a report by CNN, the letter warned that should Israel fail to make more humanitarian aid accessible to Gazans, the country would risk violating US laws governing foreign military assistance. As a result, US military aid to Israel could be in jeopardy.

The letter noted that under US laws, the state and defense departments must continually assess Israel's adherence to its assurances that it would not restrict aid flows into Gaza.

The 30-day period given by the United States means that potential consequences, if any, in the event that Israel does not heed US warnings will occur after the US presidential election on Nov 5.

Asked to explain the deadline, US National Security Council spokesperson John Kirby referred reporters to the State Department for an explanation, saying that the Biden administration also sent a letter to Israel back in April in which it "made a similar request for concrete measures with respect to humanitarian assistance."

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Kirby said the latest letter was "tied to a recent decrease" in the flow of humanitarian assistance into Gaza. "But it's not like we haven't communicated these concerns in writing before to the Israelis," he added.

At least 26 Palestinians were killed on Tuesday in Israeli attacks across the Gaza Strip, according to Palestinian medical and security sources.

Medical sources said 11 Palestinians were killed in Israeli shelling near the al-Faluja area in Jabalia refugee camp, while at least 10 others were killed in an airstrike targeting an inhabited house east of Khan Younis city in southern Gaza.

They added five more were killed in the Israeli bombing of a house in the Nuseirat camp in central Gaza, noting they were all transferred to Al-Aqsa Hospital.

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According to Palestinian security sources, Israeli tanks continue to besiege the Jabalia refugee camp for the 11th day in a row, as residents of Jabalia, its camp, and the nearby cities of Beit Hanoun and Beit Lahia were ordered to evacuate southward.

Israel has been conducting a large-scale offensive against Hamas in Gaza to retaliate against a Hamas rampage through the southern Israeli border on Oct 7, 2023, during which 1,200 people were killed and about 250 others taken hostage.

The Palestinian death toll from ongoing Israeli attacks in Gaza has risen to 42,344, Gaza-based health authorities said in a statement on Tuesday.