Israel bracing for attack after assassinations in Beirut and Tehran

TEL AVIV — Israel is bracing for a potential multiday attack by Iran and its ally Hezbollah following the assassination of two senior militant leaders last week, an Israeli official told NBC News.

The official said Israel fears waves of missiles and drones could be fired over several days in response to the killing of Hamas political leader Ismail Haniyeh and Hezbollah commander Fuad Shukr.

"They'll just try to wear us out," the official said.

This tension marks yet another escalation in the Middle East during the 10 months of the Israel-Hamas war, characterized by a series of heightened stress points amid worries that an all-out regional conflict is on the horizon.

Israel killed Shukr in a strike on the southern suburbs of Beirut last Tuesday. The strike in the largely Shia neighborhood also killed three civilians, including two children, and injured 74 others, according to the Lebanese health ministry.

Israel's military blamed Shukr for an attack in the Israeli-controlled Golan Heights that killed 12 children, saying there was no price too high for the "blood of our people." Hezbollah denied responsibility for that attack.

Hours later, news broke that Haniyeh was killed in Tehran in the early hours Wednesday morning. Haniyeh was in Iran to attend the inauguration of the new Iranian President Masoud Pezeshkian.

President Joe Biden spoke to Prime Minister Benjamin Netanyahu the day after Haniyeh's assassination. The president has said publicly that the killing was not helpful to U.S. efforts to reach a cease-fire in Gaza. The call was "tense," according to the Israeli official.

"There is strong U.S. pressure to reach a cease-fire," the official said. "Biden wants it to happen during his time in office."

Israeli negotiators were