“We recognize Israel’s right to defend itself from terrorism and other security threats, consistent with international humanitarian law,” a State Department statement said. “We will continue to do what is necessary to ensure Israel can defend itself in the face of these threats.”

U.S. officials said the White House considered a number of factors — including daily developments in Gaza, last month’s visit to Washington by Prime Minister Benjamin Netanyahu of Israel and concerns about retaliation by Iran and its proxies, especially after the assassinations of senior Hamas and Hezbollah leaders — in deciding when to formally approve the sales. The timing of the announcement also intended in part to avoid an ugly fight in Congress at a time when the Biden administration is trying to broker a cease-fire. Congress is not in session this month, and a 15-day clock for lawmakers to try to block the sales runs out next week.

Bradley Bowman, a former U.S. Army officer and senior military expert at the Foundation for Defense of Democracies, a Washington research group, said the White House is calculating that the announcement of the arms sales could have an immediate deterrent effect.

“We are sending extraordinary combat power to the region to deter a wider regional war, and we are saying we will be delivering vital capabilities to Israel for years to come,” Mr. Bowman said. “That’s an important message from the world’s leading military power as Israel confronts extraordinary threats.”

The war in Gaza — and how it has divided the American public — has put a spotlight on the normally lengthy, technical process by which U.S. weapons producers sell arms to foreign governments.

Here is a look at the arms sales that the Biden administration notified Congress on Aug. 13 that it has approved.

F-15 fighter jets

Up to 50 new F-15 IA jets, and upgrade kits for the 25 F-15 I aircraft that Israel already has, are at the core of the $18.8 billion purchase that Congress was first informally notified about in January. The deal was initially delayed by the top Democrats on the House and Senate foreign affairs committees amid concerns about Israel’s tactics in Gaza, but they agreed in June to let it move forward.

The package with Boeing Corp. also covers an array of equipment for the jets — including 120 engines, 75 radars, 320 missile launchers and 180 GPS devices, among other technology. None of it is expected to be delivered until 2029.

The F-15s will help Israel “meet current and future enemy threats, strengthen its homeland defense and serve as a deterrent to regional threats,” the Defense Security Cooperation Agency said in its announcement of the approval.

Tank ammunition

Israel plans to buy 32,739 tank cartridges of 120-millimeter rounds from military contractors General Dynamics and Northrop Grumman for an estimated $774.1 million. The sale would also include various tank munitions, canisters and support services, with deliveries beginning in 2027.

The informal notification of the proposed sale was sent to Congress in May, according to reports in The Wall Street Journal and CNN. It was part of initial discussions between Congress and the State Department to also sell tactical vehicles and mortar rounds to Israel, in an arms package totaling $1 billion. The final notification for the vehicles and mortars was also sent to Congress on Aug. 13.

Tactical vehicles

The sale of eight-ton cargo trucks is valued at $583 million. The trucks, which would be delivered starting in 2026, are used for freight transport, unit resupply and other tactical missions to support combat units.

The notification does not specify how many of the trucks Israel plans to buy from the manufacturer, the Oshkosh Corp., but says the total sale would include an earlier, $62.4 million order for the trucks, spare parts, software delivery and other support.

Mortar rounds

Israel plans to buy 50,400 120-millimeter high-explosive cartridges for mortars, a kind of portable cannon. The sale, totaling $61 million, includes 400 rounds from an earlier proposed sale from General Dynamic Ordnance. They will be delivered starting in 2026.

Medium-range missiles

The U.S. has approved the sale of 30 medium-range, air-to-air missiles from the AIM-120 C-8 series. The missiles are considered “a key aerial combat capability used to defend against airborne threats, such as the missile and drone salvo launched at Israel on April 14,” according to a statement from the Defense Security Cooperation Agency.

The notification did not say when the missiles would be delivered to Israel, and a U.S. official who spoke on condition of anonymity because he wasn’t authorized to speak on the record said it is possible that some could be sent in the next year, based on production capacity. They are being sold to Israel by RTX Corp. for $102.5 million.

The AIM-120 C-8 series, known as an “AMRAAM” are used by militaries around the world. In Ukraine, AMRAAMs are expected to arm the fleet of F-16 fighter jets that European governments are sending to help Kyiv defend its country from Russia.

The autopsy reports have not been made public. The New York Times has not reviewed them and cannot confirm the results.

Four other bodies found in the tunnels near the hostages, believed to belong to Hamas militants, did not display the same marks, the military spokesperson said.

How and when the hostages died has been a matter of contention. Hamas has blamed the deaths on Israeli airstrikes, and the Israeli military has acknowledged some of them likely died while Israel was carrying out military operations in the area where they were found. Some Israel news outlets reported the hostages may have suffocated when the tunnel filled with toxins after an airstrike.

The revelations raise new questions about the circumstances of the hostages’ deaths after months of conflicting statements about some of the recovered captives from Hamas and the Israeli military.

On Tuesday, the Israeli military announced that it had recovered the six bodies in a hidden tunnel network, alongside four of their presumed captors.

Five of the six captives were already believed to be dead, according to the Israeli military. Three of them — Haim Peri, 80; Yoram Metzger, 80; and Alexander Dancyg, 75 — had been abducted from the Nir Oz kibbutz near the Gaza border. Two others — Nadav Popplewell, 51, and Yagev Buchshtab, 35 — were taken from another border community, Nirim.

The sixth body belonged to another resident of Nir Oz, Avraham Munder, 79. Mr. Munder’s death had not been established previously.

Abu Ubaida, a spokesman for Hamas’s military wing, said in March that Mr. Metzger and Mr. Peri were among seven hostages who had been killed in Israeli airstrikes in Gaza. Hamas then said in May that Mr. Popplewell had died from injuries sustained in an Israeli airstrike more than a month earlier.

Weeks later, in early June, the Israeli military’s chief spokesman, Rear Adm. Daniel Hagari, said that it was examining the possibility that some of the hostages had been killed together months earlier while Israeli forces were operating in the Khan Younis area.

On Tuesday, Adm. Hagari was asked again about how the hostages died at a news conference. He repeated what he had said in June — that the “hostages were killed while our troops were operating in Khan Younis” — and added that a forensic examination would reveal more.

Israeli news media reported on Tuesday that initial assessments suggested that five of the six hostages had died from suffocation when an Israeli airstrike hit another tunnel, causing the one they were in to fill with carbon dioxide. The Times could not confirm those reports.

The recovery of six dead hostages this week emphasized the urgent need for a cease-fire deal, families of the captives said in their statement on Thursday. The forum said the evidence the hostages may have been shot “serves as further proof of the cruelty of the terrorists,” and it condemned the government’s failure to reach a cease-fire agreement that would lead to the return of all hostages and an end to the fighting in Gaza.

“In every minute that the deal is not completed, another hostage could lose their life,” the forum said. “After 10 and a half months of war in which the hostages have been suffering, tortured, and dying, it is clear to all that the return of the hostages is only possible through a deal.”