Israel Defense Forces spokesman Rear Adm. Daniel Hagari said Israel focused too intensely on the Iranian nuclear threat at the expense of its ballistic threat.

A senior U.S. official told ABC News the U.S. also relied too heavily on the misguided conception that Iran's Supreme Leader Ayatollah Ali Khamenei was cautious and would never order a direct attack on Israel, and that this weekend’s attack and the general U.S. assessment of Iran now requires study and reassessment.

Sima Shine, a former head of the Iran desk at Israeli espionage agency Mossad, also said Israel’s assessment was wrong, and said "the rules of the game" have changed. A huge barrage of missiles was considered possible, but highly unlikely, Shine said.

Shine said any Israeli response under the new conception requires the assumption that Iran will follow up with its threat of another salvo of missiles. That said, Shine believes that Iran and the supreme leader do not want a full-scale war because it would be unpopular in Iran and the U.S. could get involved.

-ABC News’ Matt Gutman

Treasury Secretary Janet Yellen is warning Iran that the U.S. "will not hesitate" to impose new sanctions in response to Iran's "unprecedented attack" on Israel.

"Treasury will not hesitate to work with our allies to use our sanctions authority to continue disrupting the Iranian regime’s malign and destabilizing activity," Yellen is expected to say at a Tuesday press conference. "The attack by Iran and its proxies underscores the importance of Treasury's work to use our economic tools to counter Iran's malign activity."

Yellen's message follows President Joe Biden's Sunday meeting with the G7 nations, during which the leaders discussed a coordinated effort on sanction measures.

-ABC News’ Justin Ryan Gomez

Prime Minister Benjamin Netanyahu's war cabinet is expected to meet again on Tuesday to consider an Israeli response to Iran's weekend attack.

"We are closely assessing the situation. We remain at our highest level of readiness," Herzi Halevi, chief of staff of the Israel Defense Forces, said on Monday. "Iran will face the consequences for its actions."

Halevi added Israel would "choose our response accordingly."

-ABC News' Morgan Winsor and Somayeh Malekian

United Nations officials called on Tuesday for Israel and Iran to de-escalate their conflict, saying the retaliatory military attacks “violate the right to life and must cease immediately.”

“All countries are prohibited from arbitrarily depriving individuals of their right to life in military operations abroad, including when countering terrorism,” the U.N.’s Office of the High Commissioner for Human Rights said in a press release, quoting U.N. officials described as "experts."

The retaliatory strikes by both countries may constitute the “international crime of aggression by civilian and military leaders responsible,” those officials said, according to the statement.

-ABC News' Kevin Shalvey

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