Israel halted its offensive against Hezbollah guerrillas as a U.N.-imposed cease-fire went into effect Monday after a month of warfare that killed more than 900 people, devastated much of south Lebanon and forced hundreds of thousands of Israelis into bomb shelters. A half hour after the cease-fire took hold, Israeli warplanes — a regular fixture in Lebanese skies during the monthlong war — were absent across huge swaths of the country, including the Bekaa Valley, where airstrikes hit about an hour before. Full Story