srael was on high alert for an escalation with Hezbollah on Wednesday after one of the top leaders of the Palestinian Hamas was killed in a strike in Beirut that was widely blamed on Israel and heightened the risk of a broader Middle East conflict. The killing of Saleh Arouri, the most senior Hamas member slain since the war in Gaza erupted nearly three months ago, provided a morale boost for Israelis still reeling from Hamas' Oct. 7 attack as the militants put up stiff resistance in Gaza and continue to hold scores of hostages. But its implications for the war remain unclear. Israel has killed several top Hamas leaders over the years, only to see them quickly replaced. And the strike in Hezbollah's southern Beirut stronghold could cause the low-intensity fighting along the Lebanon border to boil over into all-out war. Much depends on how Hassan Nasrallah — who has led Hezbollah since an Israeli strike killed his predecessor in 1992 — chooses to respond. He has previously vowed to retaliate for any Israeli targeting of allied militant leaders in Lebanon, and was expected to deliver a speech at 6 p.m. (1600 GMT). Hezbollah and the Israeli military have been exchanging fire almost daily over the Israeli-Lebanese border since the war in Gaza began, but Nasrallah has appeared reluctant to escalate it further, perhaps fearing a repeat of the monthlong 2006 war, in which Israel heavily bombed Beirut and southern Lebanon. Hezbollah announced a flurry of rocket launches into northern Israel late Tuesday but did not directly link them to the killing of Arouri. Journalists in southern Lebanon reported heavy Israeli shelling and airstrikes. But there were no reports of casualties, and by early Wednesday the border area was calm. Israeli officials have not commented on the strike that killed Arouri, but Rear Adm. Daniel Hagari, an Israeli military spokesman, said “we are on high readiness for any scenario.” The United States has sought to prevent any widening of the conflict, including by deploying two aircraft carriers and other military assets to the region. Secretary of State Antony Blinken was expected in the region this week.