Israel pummeled Lebanon with airstrikes Monday that killed 274 people and left more than 1,000 injured, according to the Lebanese health ministry, marking the deadliest day for Lebanon since Israel and the militant group Hezbollah ramped up their exchange of fire nearly a year ago. In a dramatic escalation, Israel said it struck 800 targets in Lebanon, carrying out what an Israeli military spokesman called “extensive, precise strikes.” Israeli Prime Minister Benjamin Netanyahu, who on Sunday...