CAIRO — This week saw a dizzying escalation in the 11-month-old conflict between Israel and Lebanon’s Hezbollah. First came two days of exploding pagers and walkie-talkies used by Hezbollah — deadly attacks pinned on Israel that also maimed civilians around Lebanon.

Hezbollah pounded northern Israel with 140 rockets Friday, a day after the militant group’s leader vowed to retaliate against Israel for a mass bombing attack, the Israeli military and the militant group said.

Israel launched a rare airstrike that killed a senior Hezbollah military official in a densely populated southern Beirut neighborhood on Friday. It was the deadliest such strike on Lebanon’s capital in decades,