A United States assessment shows a retaliatory attack by Iran and its proxies against Israel could be launched "this week," the White House said Monday.

"We share the same concerns and expectations that our Israeli counterparts have with respect to potential timing here. Could be this week," National Security Council spokesperson John Kirby told reporters. "We're continuing to watch it very, very closely."

Kirby said it's difficult to ascertain what a potential attack could look like at this time but that "we have to be prepared for what could be a significant set of attacks."

Meanwhile, Israel Defense Forces spokesperson Daniel Hagari told reporters on Monday that Israel remains "on high alert."

"We take seriously the threats of our enemies and that is why we are on high alert offensively and defensively," he said.

Hagari said the IDF will "work hard to give the public time to get organized."

-ABC News' Justin Gomez

Israeli Defense Minister Yoav Gallant appeared to take a swing at Israeli Prime Minister Benjamin Netanyahu during a Knesset committee meeting about Israel’s response to ongoing cross-border tensions with Lebanese militant group Hezbollah.

"I hear all the heroes with the war drums, the 'absolute victory' and this gibberish," Gallant reportedly said, alluding to Netanyahu's slogan through the war, according to Israeli media.

Netanyahu's office released a statement shortly after, saying Gallant too is bound by the policy of "absolute victory."

"When Gallant adopts the anti-Israel narrative, he hurts the chances of reaching a deal for the release of the abductees," the Israeli Prime Minister's Office said. "He should have attacked [Hamas leader Yahya] Sinwar, who refuses to send a delegation to the negotiations, and who was and remains the only obstacle to the kidnapping deal."

National Unity Party Chairman Benny Gantz warned about internal divisions in Israel during an address on Monday.

"If we don't come to our senses, there will be a civil war here," Gantz said.

He said there have been "heroes," from soldiers to volunteers, in the wake of the Oct. 7 attack, but also "leadership that dissolves, networks that poison the well from which we live."

"The patriotic Israeli majority should stop the hatred and make amends," Gantz said.

-ABC News' Jordana Miller

While the weekend passed with no direct retaliation from Hezbollah for the killings of several top leaders by Israeli strikes, the group said it still plans to strike.

"The response is coming and inevitable and there is no turning back from it," Ali Damoush, the deputy chairman of the Executive Council of Hezbollah, said Monday.

The Hezbollah official saif America, Great Britain, Germany and everyone who supplies Israel with weapons is a partner in the Gaza massacres.

"Israel does not find any practical and serious response to its massacres, and this is what encourages it to continue committing crimes and massacres, and without effective pressure Netanyahu will not stop his crimes," Damoush claimed.

Amid fears that an attack from Iran may be imminent, the commander of Israel’s Air Force, Maj. Gen. Tomer Bar, has issued an order barring servicemembers from traveling abroad. The directive applies to career officers and non-commissioned officers, not conscripts, according to the Israel Defense Forces.

-ABC News' Jordana Miller