BEIRUT, Lebanon — Israeli airstrikes Saturday in central Beirut killed at least 15 people, officials said, as the once-rare attacks on the heart of Lebanon’s capital continued without warning while diplomats scrambled to broker a cease-fire. [time-brightcove not-tgx=”true”] Lebanon’s Health Ministry said 63 people were wounded in the strikes, which were the fourth in central Beirut in less than a week. The escalation comes after U.S.