An independent, self-formed task force of former State Department officials and international law experts say the U.S. "shirked" its legal obligations with Friday's National Security Memorandum-mandated report that examined Israel's use of U.S.-supplied arms.

"The Administration must come to terms with the fact that what it faces in its lethal military assistance to Israel's operations in Gaza - and beyond - is not a policy problem: it is a legal problem," the officials said Friday, adding, "The Administration’s report is at best incomplete, and at worst intentionally misleading in defense of acts and behaviors that likely violate international humanitarian law and may amount to war crimes. Once again, the Biden Administration has stared the facts in the face - and then pulled the curtains shut."

More than 34,000 Palestinians have died, including 14,000 children, the officials said, noting that "most of them [were] killed by U.S. munitions."

-ABC News' Christopher Boccia

A new report from the United States Departments of State and Defense said that given "Israel's significant reliance on U.S.-made defense articles" it is "reasonable to assess" that some have been used in instances "inconsistent" with Israel's obligation under international law.

The assessment, which came as part of a report ordered by President Joe Biden, examined the use of U.S.-supplied arms in active conflict zones, and also said that the U.S. could not compile enough evidence to prove that the country used American defense articles in violation of international humanitarian law.

"We do not have complete information to verify whether US defense articles covered under NSM-20 were specifically used in actions that have been alleged as violations of IHL (international humanitarian law) or international human rights law during the period of the report," the document says. "The nature of the conflict in Gaza makes it difficult to address or reach conclusive findings on individual incidents."

While the report said the Israeli government has "the knowledge, experience, and tools" to implement "best practices for mitigating civilian harm," the high number of civilian casualties "raise substantial questions about whether the IDF is using them effectively in all cases."

Additionally, the report noted that Israel did not cooperate with U.S. efforts to ramp up humanitarian aid and distribution in Gaza during the initial months of the conflict, but that officials have observed improvements.

-ABC News' Shannon Crawford and Anne Flaherty

An upcoming report from the Biden administration examining Israel’s use of American-supplied arms does not conclude that the country violated international or U.S. law in Gaza, according to two sources familiar with the assessment, which has not yet been released.

Despite these findings, the report is still highly critical of some of the actions Israel has taken through the course of its military campaign against Hamas, a U.S. official added.

-ABC News' Shannon Crawford and Ben Siegel

Hamas says negotiations with Israel for a permanent cease-fire have fallen through after Israel rejected its proposals, including demands for a permanent cease-fire, complete withdrawal of Israel's forces from Gaza, the return of displaced people and a prisoner exchange.

"Israel's rejection of the mediators' proposal, through the amendments it made to it, has brought things back to square one," Hamas said in a statement Friday.

Hamas said Israel bears "the full responsibility" for the failure to reach an agreement.

"The enemy's army's attack on Rafah and the direct occupation of the crossing immediately after Hamas announced its agreement to the mediators' proposal confirms that the occupation is evading reaching an agreement. Netanyahu and his extremist government are using negotiations as a cover for the attack on Rafah and the occupation of the crossing, and continuing the genocide against our people," Hamas said.

Although the Biden administration said it expected the Kerem Shalom and Rafah gates to be at least partially opened for humanitarian aid by Wednesday, the State Department was much less optimistic. However, the U.S. vowed it would continue to press Israel to get both portals up and running again.

While Kerem Shalom reopened Wednesday, aid had not been allowed to pass through because of "logistical and security concerns on the ground," State Department spokesperson Matt Miller said during a briefing Wednesday. He also said fuel had not been able to enter Gaza through Rafah.

"We think it's critical that Rafah be open for fuel because without fuel deliveries into Rafah, humanitarian assistance that comes in through Kerem Shalom can't actually be delivered. The two are critically linked," Miller said. "We're continuing to push for that to happen."

Miller didn’t provide any updated timeline on when the U.S. expected the crossings would be functional again, but said it was imperative that Israel act to increase the amount of aid allowed into Gaza following what he described as a "fairly dramatic dip" this week.

"When it comes to the level of humanitarian assistance, the results as they are today are just unacceptable. There's no other way to put it," Miller lamented.

He continued, "We are making quite clear to the government of Israel that we need to see those decreases reversed. We need to get back to where we were, and we need to see the levels continue to increase and see those sustained, and that is why we need to see Kerem Shalom and Rafah opened."

-ABC News' Shannon Crawford