Israel-Gaza-Lebanon updates: Iranian president responds to Israel's retaliatory attacks

Seven Israeli citizens were arrested after allegedly spying for Iran, Israeli authorities said Monday.

The Israel Security Agency and Israel Police said they "successfully dismantled a spy network" that allegedly gathered sensitive information on Israel Defense Forces bases and energy infrastructure.

The citizens were allegedly recruited by Iranian agents to conduct "security-related tasks" over at least two years, authorities said, including "extensive reconnaissance missions" on air force and navy installations, ports, Iron Dome system locations and energy infrastructure.

Photographs and videos of "numerous" IDF bases, ports and energy infrastructure were seized as part of the investigation, authorities said.

"It is assessed that these activities have inflicted security damage on the state," the ISA and Israel Police said.

The seven Israelis were allegedly paid hundreds of thousands of dollars, often through cryptocurrencies, for their work, authorities said.

Prosecutors are expected to file an indictment against them in the coming days.

U.S. Defense Secretary Lloyd Austin told reporters while traveling to Ukraine on Monday that it's "hard to say" what an Israeli retaliatory strike on Iran will look like, when asked whether the response should be proportional.

"That's an Israeli decision," he said. "Whether or not the Israelis believe [it] is proportional and [how] the Iranians perceive it, I mean, those are maybe two different things."

Austin told reporters that the U.S. is "going to continue to do everything we can" to get both parties to "begin to de-escalate."

-ABC News' Luis Martinez

Secretary of State Antony Blinken will begin a tour of Israel and other Middle Eastern nations on Monday in a bid to inject new life into stalled cease-fire and hostage release negotiations in Gaza, the State Department said.

Blinken "will discuss the importance of bringing the war in Gaza to an end, securing the release of all hostages and alleviating the suffering of the Palestinian people," the State Department notice said.

"He will continue discussions on post-conflict period planning and emphasize the need to chart a new path forward that enables Palestinians to rebuild their lives and realize their aspirations free from Hamas' tyranny," the statement said.

Blinken will also "underscore that additional food, medicine and other humanitarian aid must be delivered to civilians in Gaza," it continued.

The situation in Lebanon -- where Israel is continuing an intense air and ground campaign and Hezbollah is still firing across the shared border -- will also be a topic of discussion, the State Department said.

Blinken will continue pursuit of a "diplomatic resolution" that "allows civilians on both sides" of the border to return to their homes, the statement said.

-ABC News' Cindy Smith

"Beirut in flames," Israeli Foreign Minister Israel Katz wrote on X on Monday following an intense night of airstrikes on the Lebanese capital.

"A wide-scale Israeli attack targeted Hezbollah's financial infrastructure in Beirut and across Lebanon last night," Katz said.

"Massive fires were seen above Beirut as over 15 buildings were struck following evacuation warnings to residents," the foreign minister wrote.

"Hezbollah has paid and will continue to pay a heavy price for its attacks on northern Israel and its rocket fire. We will keep striking the Iranian proxy until it collapses."

-ABC News' Guy Davies