If Israel strikes back, the response speed from Iran "will be less than a few seconds," said Ali Bagheri Kani, the deputy foreign minister of Iran for political affairs.

Maj. Gen. Pat Ryder, the Pentagon press secretary, said Monday that Iran did not give the U.S. an advanced notice of its attack on Israel.

"I think what you're asking was did Iran give us a heads up? No, they did not," Ryder said, without indicating whether the U.S. learned of Iran's plans through allies.

Ryder said U.S. forces in the Middle East intercepted dozens of missiles and unmanned aerial vehicles when Iran and its proxies launched attacks in retaliation for Israel's strike earlier this month on the Iranian Consulate in Damascus, Syria, that killed an Iranian military leader.

Ryder repeated assessments that 99% of incoming Iranian fire was intercepted by Israel and its partners, but he wouldn't confirm reports that half of the launches failed to get off the ground.

Secretary of Defense Lloyd Austin, Ryder said, has spoken with Israeli Defense Minister Yoav Gallant three times since the attack.

"During their most recent call yesterday, the two leaders reviewed the successful combined operation by the United States, Israel and their partners to defend Israel from these unprecedented attacks by Iran and its proxies and emphasize that while the United States does not seek escalation, we will continue to take all necessary action to defend Israel and U.S. personnel," Ryder said.

Asked whether the response to Iran's attack depleted the air defense resources of Israel and its partners, Ryder declined to answer.

"As we demonstrated this weekend, we have the capability and the capacity to defend Israel and to defend our forces in the region," he said.

-ABC News' Chris Boccia and Matt Seyler

As Israel's Chief of the General Staff Herzi Halevi met with troops at the Nevatim Airbase, where Iranian missiles struck over the weekend, he said Israel is weighing possible response actions.

"As we look forward, we weigh our steps, and this launch of so many missiles, cruise missiles, UAVs to the territory of the State of Israel will be met with a response," Halevi said.

-ABC News’ Jordana Miller

As Israel on Monday weighed its response to Iran’s weekend attack, the U.S. is privately telling officials there: If Israel strikes back militarily, it will do so alone.

It's an unusual message for a close ally that's spent decades receiving more U.S. military aid than any other country in the world and whose relationship with America is often described as "ironclad."

But after months of Israel acting on its own in Gaza -- and facing tough criticism from the U.S. and other allies that its military operations have gone too far – the Biden administration made clear the U.S. wouldn't participate in offensive military operations against Iran, fearing a broader war in the Middle East.

"We believe Israel has freedom of action to protect itself and defend itself," a senior administration official told reporters shortly after Iran's attack ended. "That's a long-standing policy, and that remains."

When asked by a reporter if the U.S. would help Israel counter with offensive military operations, the official said no.

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-ABC News’ Anne Flaherty

President Joe Biden called for an immediate cease-fire to get food and aid into Gaza in an interview airing Tuesday night on Univision.

"So I what I'm calling for is for the Israelis to just call for a cease-fire, allow for the next six, eight weeks total access to all food and medicine going into the country," Biden said in the interview with Univision's Enrique Acevedo. "I've spoken with everyone from the Saudis to the Jordanians to the Egyptians. They're prepared to move in. They're prepared to move this food in. And I think there's no excuse to not provide for the medical and the food needs of those people. It should be done now."

Biden did not mention tying the cease-fire to a hostage deal, according to a transcript of the interview, which would be a shift for the administration. ABC News has reached out to the White House for comment.

Last week, officials pushed back on suggestions that they were separating calls for a cease-fire from hostage negotiations in their readout of Biden's call with Israeli Prime Minister Benjamin Netanyahu.

"Our conviction remains that we need to see an immediate cease-fire to enable the release of hostages but also to enable a dramatic surge in humanitarian assistance, as well as obviously better protecting civilians," Secretary of State Antony Blinken said on April 4.

In the Univision interview, Biden also called Netanyahu's approach in Gaza "a mistake" when asked if he believed the prime minister was "more concerned about his political survival than he is in the national interest of his people" as calls for Netanyahu's resignation have increased following the strike that killed seven World Central Kitchen workers.

"Well, I will tell you, I think what he's doing is a mistake. I don't agree with his approach. I think it's outrageous that those four, three vehicles were hit by drones and taken out on a highway where it wasn't like it was along the shore, it wasn't like there was a convoy moving there, etc.," Biden said in the interview.

The hour-long interview, which is airing at 10 p.m. ET, was taped a day before Biden's call with Netanyahu on April 4.

-ABC News' Molly Nagle