The Biden administration is pressing Congress to approve a plan to sell $18 billion worth of F-15 fighter jets to Israel, as President Biden resists calls to limit U.S. arms sales to Israel over its military offensive in Gaza.

The State Department recently sent an informal notice to two congressional committees to start a legislative review process for the order, a first step toward the department’s giving formal authorization for the transfer of up to 50 of the planes.

The F-15 order was reported earlier by Politico and CNN and confirmed by two U.S. officials. The deal, which would be one of the largest U.S. arms sales to Israel in years, would also include munitions, training and other support.

Although the United States has expedited some arms for Israel’s current campaign against Hamas, the F-15s would not be delivered for at least five years, the U.S. officials said.

With a top speed of nearly 2,000 miles per hour, the F-15 is capable of both air-to-air combat and bombing targets on the ground. While Israel has used the F-15s it already owns to strike Gaza, its request for the planes appears to reflect longer-term concern about regional threats, including from Lebanon-based Hezbollah, Iran-backed militias in Syria, and Iran itself. The Israel Defense Forces would probably employ F-15s in any potential attack on Iran’s nuclear program.

Israeli officials have also told their U.S. counterparts that Israel is about to place a new order for F-35 jets, a U.S. official said.

The United States steadily delivers weapons to Israel as part of a 10-year agreement to provide $3.8 billion in annual military aid that the Obama administration finalized in 2016. Many arms orders placed since then and that are being filled now have already been approved by Congress.

But the Biden administration has also rushed two new emergency shipments of weapons to Israel totaling more than $250 million since the Oct. 7 terrorist attacks in Israel by Hamas, bypassing congressional approval on the grounds that the arms, mainly artillery and tank ammunition, were needed immediately.

And if Israel’s orders do not meet a certain dollar threshold, then the administration does not need to notify Congress or get its approval. So some orders placed since Oct. 7, perhaps dozens or more, have not been publicly disclosed, U.S. officials said.

Critics of Israel’s campaign in Gaza — in which more than 32,000 Palestinians have been killed, according to health ministry officials there — say that the Biden administration should use any available leverage to make Israel change its approach.

Speaking at a news conference in Paris on Tuesday, Secretary of State Antony J. Blinken did not specifically address the potential F-15 sale. But he defended the Biden administration’s continued transfer of weapons to Israel generally and stressed that most recent ones have not been directly related to the current conflict in Gaza.

Such transfers are part of agreements that “go back a decade or more” and involve weapons systems that can require years to manufacture, Mr. Blinken told reporters. Those cases, he said, “underwent congressional review years ago and were notified years ago, well before the conflict in Gaza started.”

Mr. Blinken indicated that the United States was determined to protect Israel’s wider security concerns, beyond the Gaza conflict.

“It’s also about the threats posed to Israel by Hezbollah, by Iran, by various other actors in the region, each one of which has vowed one way or another to try to destroy Israel,” he said.

After Oct. 7, Israel requested expedited transfers of orders that had been approved years ago, including bombs ranging from 250 pounds to 2,000 pounds, which Israel drops regularly in Gaza but which the U.S. military and many allies prefer not to use in urban warfare.

A State Department official said that the department as a rule does not confirm or deny U.S. arms transfers before they are formally notified to Congress. The official added that after Congress approves an arms sale to Israel, it can be completed in dozens of individual deliveries over many years. These deliveries do not require a separate notification to Congress.

Some U.S. officials privately say that slowing, reducing or conditioning arms sales to Israel might embolden Iran and its regional allies, and weaken Israel’s deterrent power against them.

But critics of Israel’s military campaign in Gaza are unmoved by such arguments, saying that the Biden administration’s repeated calls for Israel to better protect Gazan civilians have had little effect and must be enforced with tangible consequences.

“The Biden administration needs to make better use of the tools we have, including the transfer of offensive weapons, to enforce President Biden’s reasonable requests,” said Senator Chris Van Hollen, Democrat of Maryland.

Mr. Van Hollen, referring to Prime Minister Benjamin Netanyahu of Israel, complained that the “extreme Netanyahu government continues to rebuff the Biden administration at every turn — from disregarding calls to allow more aid to reach starving people in Gaza to insisting that it will launch an invasion of Rafah despite President Biden having drawn a ‘red line.’”

The F-15s were on a list of requests raised last week by Israel’s defense minister, Yoav Gallant, in his meetings with administration officials in Washington, according to a U.S. official briefed on the conversations. Mr. Gallant also said Israel wants to acquire more F-35 fighter jets from the U.S.

That would be separate from Israel’s recently exercising an option in an existing order of F-35s to buy $2 billion more of the jets and equipment.

Israel already owns dozens of F-35s, which are among the most advanced weapons in America’s military arsenal.

It likewise operates a fleet of F-15s, which it has used for strikes in Gaza but also relies on for longer-range missions to places like Lebanon and Syria. In 2016, a senior official in Israel’s air force said that the plane was valuable “when we want to reach far distances with few aircraft.”

An April 1 policy briefing document from the Jewish Institute for National Security for America said that Israel needed F-15 and F-35 fighters to “eliminate Hezbollah personnel and weapons arsenals in Lebanon.”

“Fighter aircraft also provide support to IDF ground forces in Gaza and enable Israel to conduct operations against hostile actors in Syria and elsewhere across the region,” wrote Yoni Tobin, an analyst for the hawkish think tank, which has ties to Israel’s government and military. Mr. Tobin added that the planes were necessary for Israel to maintain decisive military superiority over its regional rivals, known in policy circles as qualitative military edge, or QME.

Speaking to reporters at the White House, John F. Kirby, a White House national security spokesman, said on Tuesday that he believed the administration’s approach was working.

But some in Congress disagree.

“The United States wants Israel to let in more humanitarian aid, stop bombing civilians and not invade Rafah,” Senator Bernie Sanders, independent of Vermont, said on Tuesday. “Netanyahu has ignored all of it. Why are we still sending him taxpayer dollars and weapons and expecting a different outcome?”

Robert Jimison contributed reporting.