As Iran retaliates, largest US military base in Middle East hit by ballistic missile, Qatar says

The Israel Defense Forces said in a statement that its expanded strikes in Lebanon -- including on the capital Beirut -- were a response to Hezbollah's launch of "several rockets and UAVs" from Lebanese territory toward Israel.

The IDF targets included "command posts, infrastructure and a vehicle carrying two Radwan operatives near the area of Kafr D'gal," the IDF said.

The IDF noted that its "significant" strikes against Hezbollah in southern and eastern Lebanon had been ongoing -- despite a November 2024 ceasefire -- prior to the launch of the U.S.-Israeli operation against Iran on Saturday.

-ABC News' Jordana Miller and Will Gretsky

The Israel Defense Forces said early on Monday that it had detected missiles launched from Iran toward Israel.

"Defensive systems are operating to intercept the threat," the IDF said. "In the past few minutes, the Home Front Command has sent a precautionary directive directly to mobile phones in the relevant areas."

Authorities in Bahrain separately issued an alert, saying a siren had been sounded.

"Citizens and residents are urged to remain calm and head to the nearest safe place," Bahrain said.

-ABC News’ Will Gretsky

In a statement on Monday, amid ongoing strikes against Lebanon, the Israel Defense Forces said, "The strikes continue — their intensity will increase.”

Overnight, the IDF had launched a series of strikes in Beirut and Southern Lebanon. The IDF said senior Hezbollah members were targeted in the Beirut area among the strikes.

Earlier on Monday, Lebanon had launched projectiles toward northern Israel that were intercepted.

"Shortly after Hezbollah’s rocket fire, in accordance with planning, we launched a first broad wave of strikes in Beirut and southern Lebanon, targeting senior operatives, headquarters, and terrorist infrastructure. We are also acting to evacuate civilians in southern Lebanon ahead of further strikes," the IDF said.

Secretary of the Supreme National Security Council of Iran, Ali Larijani, released a statement on X on Monday, saying, "We will not negotiate with the United States."

Larijani's statement was in response to a report about a possible resumption of talks with the U.S. in the wake of the operation in Iran over the weekend.

In another post, Larijani mentioned the American casualties in the operation, which left three U.S. service members killed and five wounded.

"Trump plunged the region into chaos with his 'delusional fantasies' and now fears more American troop casualties," Larijani said.

"Today, the Iranian nation is defending itself. The armed forces of Iran did not initiate the aggression," he added.