(NewsNation) — White House officials said Monday that Iran could launch a strike on Israel as soon as this week, so the United States and its allies are preparing for “a significant set of attacks.”

These comments, made by National Security spokesman John Kirby at a press briefing, corroborate a new assessment from the Israeli intelligence community first reported Sunday by Axios political reporter Barak Ravid. Two sources in the community believe Iran plans to “attack Israel directly” in retaliation “for the assassination of Hamas political leader Ismail Haniyeh,” according to Ravid.

An Iranian retaliation may occur “even before the Aug. 15 hostage deal talks,” Ravid added.

Drafted in the last 24 hours, this assessment represents a shift from Iran’s previous plans. On Friday, Iran’s mission to the United Nations said in a statement that “we hope that our response will be timed and conducted in a manner not to the detriment of the potential ceasefire.”

Israel’s military chief spokesperson Rear Adm. Daniel Hagari said the Israeli army and security agencies are “closely following all developments in Iran. ” Israel has “very extensive plans of attack and a high readiness to carry them out” on a number of different fronts, Hagari added.

United States President Joe Biden had a call with France, Germany, Italy and the United Kingdom Monday where the countries expressed full support for efforts to de-escalate tensions in the region, as well as a cease-fire and hostage release deal in Gaza.

A joint statement from the countries stressed there is no further time to lose.

“All parties must live up to their responsibilities,” the statement said. “In addition, unfettered delivery and distribution of aid is needed.”

During the meeting, the U.S., U.K., France, Germany and Italy also talked about supporting Israel “against Iranian aggression and against attacks by Iran-backed terrorist groups.”

“We called on Iran to stand down its ongoing threats of a military attack against Israel and discussed the serious consequences for regional security should such an attack take place,” the countries said.

Kirby told reporters that Biden is “confident” the U.S. has the capability to help defend Israel “should it come to that.”

“Nobody wants to see it come to that,” he said.

US sends guided missile sub: Pentagon

A guided missile submarine will head to the Middle East due to rising tensions between Israel, Iran and Lebanon, as ordered by U.S. Defense Secretary Lloyd Austin on Sunday evening, Reuters reports.

The Lincoln, which was in the Asia Pacific, had already been sent to the region to replace the USS Theodore Roosevelt aircraft carrier strike group. Pentagon officials said they ordered the USS Abraham Lincoln strike group to speed up its deployment to the area.

It wasn’t clear Sunday how much more quickly the Lincoln, which has F-35 fighter jets aboard and  F/A-18 fighter aircraft on carriers, will get to the Middle East.

The announcement about the USS Abraham Lincoln came a day after an Israeli airstrike hit a school-turned-shelter in Gaza, killing at least 80 people and wounding nearly 50 others, according to the Associated Press. It was one of the deadliest attacks of the 10-month Israel-Hamas war.

IDF: Lebanon launches 30 rockets

Lebanon launched 30 rockets toward northern Israel Sunday night, according to a post on the Israel Defense Force’s Hebrew-language X account. No casualties have been reported.

IDF is reportedly “striking sources of fire” following the attack, the post said.

According to The Times of Israel, Hezbollah has claimed responsibility for the projectiles, per its affiliated Al Mayadeen site.

Iran, Hamas blames Israel for Haniyeh’s death

Hamas leader Haniyeh was killed on July 31 in Iran by a presumed Israeli strike. Israel has not claimed or denied responsibility for the killing.

Yahya Sinwar, the mastermind of the Oct. 7 attacks in Israel, has since been appointed as Hamas’ new leader.

Expected retaliation for the leader’s passing has heightened tensions in the region, with world leaders hopeful the attacks will not occur before the next round of cease-fire discussions.

Iranian leaders promise revenge

In a statement to Reuters, Israeli Defense Minister Yoav Gallant warned Iran and its Lebanon-based proxy Hezbollah: “Whoever harms us in a way that has not been done in the past, is likely to be hit in a way that hasn’t been done in the past.”

Cited by Iranian media, Revolutionary Guards deputy commander Ali Fadavi said Friday that the Iranian supreme leader’s orders regarding the harsh punishment of Israel and revenge for Haniyeh are clear and will be implemented in the “best possible way”.

China supports potential Iranian retaliation

According to a statement by China’s foreign ministry, the republic supports Iran in defending its “sovereignty, security and national dignity.” Chinese foreign minister Wang Yi shared this support via phone call with Iran’s acting foreign minister, Ali Bagheri Kani, on Sunday.

Wang told Kani that the killing of Haniyeh had “directly undermined the Gaza ceasefire negotiation process and undermined regional peace and stability,” China’s foreign ministry said.

NewsNation correspondent Kellie Meyer, the Associated Press, and Reuters contributed to this report.

This is a developing story, refresh for updates.