The Biden administration is delaying shipments of ammunition that were expected to be sent to Israel, according to three U.S. officials.

The Biden administration has been trying to pressure Israel to hold off on a full-scale invasion of Rafah until it has a plan to protect the million civilians now living there.

The Air Force has been told by the White House’s National Security Council to pause shipments of ammunition deliveries specifically from Dover Air Force Base, according to a U.S. official. The NSC was behind the decision to pause the munitions, a second U.S. official confirmed.

The National Security Council did not immediately respond to a request for comment.

-ABC News' Martha Raddatz, Anne Flaherty, Matt Seyler and Ben Siegel

House Speaker Mike Johnson and Majority Leader Steve Scalise have publicly accused the Biden administration of withholding aid to Israel following reports that some aid shipments have been halted. Johnson said that the Biden administration as recently as Friday had assured his staff that there would be "no delay" in assistance to Israel.

Johnson said he received a report this morning from on the ground in Israel that said "a shipload of munitions and precision weapons, which are to be used to help protect civilians and Rafah, is being withheld."

In a letter to President Joe Biden, Senate Republicans Jodi Ernst and Ted Budd said they are "shocked" and "deeply concerned" that the Biden administration failed to notify Congress before withholding ammunition to Israel.

"If these reports are true, then you have once again broken your promise to an American ally," they said.

-ABC News' Lauren Peller and Shannon Crawford

In his first comments since Israel's offensive into Rafah began, Prime Minister Benjamin Netanyahu said that Hamas' cease-fire proposal on Monday was "intended to torpedo the entry of our forces into Rafah."

"It did not happen. As the War Cabinet unanimously determined, the Hamas proposal is very far from Israel's necessary requirements," Netanyahu said.

"I instructed the working-level delegation that went to Cairo: continue to stand firm on the conditions necessary for the release of our abductees, continue to stand firm on the essential requirements for guaranteeing Israel's security," Netanyahu said.

-ABC News' Will Gretsky

Israeli tanks controlled Gaza's Rafah border crossing early Tuesday, as military officials accused Hamas of using the crossing for "terrorist purposes."

"Following intelligence that indicated that the Rafah Crossing in eastern Rafah was being used for terrorist purposes, IDF troops managed to establish operational control of the Gazan side of the crossing," Israel Defense Forces officials said in a statement.

Mortars had on Sunday been fired "from the area," killing four IDF soldiers, the Israeli military said.

A video and photos taken by the Israeli military and released Tuesday appeared to show several Israeli tanks operating on the Gazan side of the border.

-ABC News' Kevin Shalvey

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