WASHINGTON - The airstrikes by Israeli forces that reportedly killed at least 40 people at a UN-run school in central Gaza didn't cross the so-called "red line" drawn by the United States for Israel, a US State Department spokesperson said Thursday.

The spokesperson, Matthew Miller, reiterated to reporters during a press briefing at the State Department that Washington's "red line" regarding Israel's military operation referred to a "large-scale operation in Rafah," which he said the United States has not yet seen.

"That said, we have seen strikes that put civilians in danger well before the president said that, and we have made clear to the government of Israel that we expect them to do everything that they can to minimize civilian harm," Miller said.

With regard to a CNN analysis that determined that American-supplied munitions were used during the aerial bombardments on a UN-run school in central Gaza, US State Department spokesperson Matthew Miller said that was a question better to be asked to the Israeli government

Conducted overnight by the Israeli Air Force, the airstrikes targeted a school run by UNRWA, the UN agency for Palestinian refugees, killing at lease 40 people, including 14 children, according to a CNN report citing the media office of the Hamas-run government in Gaza. The school was housing displaced people in the Nuseirat refugee camp in central Gaza at the time of the incident.

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With regard to a CNN analysis that determined that American-supplied munitions were used during the aerial bombardments, Miller said that was a question better to be asked to the Israeli government. Israel, he added, has only shared with the United States "essentially what they have said publicly" about the incident so far.

US President Joe Biden has said his country won't supply weapons to Israel if they were to be used to harm civilians.

The Israeli military said the school was being used by "Hamas and Islamic Jihad terrorists" as an operating base to stage attacks against Israel.

The Israeli strike targeted "20 to 30 terrorists" in the school compound, said Peter Lerner, spokesperson for the Israeli military, adding that efforts were made for the operation to be "as precise as possible (to) ensure limited civilian casualties."

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Expecting more information to be released by the Israeli government, Miller said at the briefing it is the United States' hope that Israel will be "fully transparent in making that information public".