GAZA CITY, Gaza Strip — An Israeli-declared temporary cease-fire and troop withdrawals slowed violence in the Gaza war Monday, though an attack on an Israeli bus that killed one person in Jerusalem underscored the tensions still simmering in the region. Several cease-fires have broken down during the 3½-week war — including Friday when an internationally negotiated truce collapsed amid violence and mutual recrimination between Israel and Hamas. But with Hamas rocket fire tapering off over the last 24 hours and Israel's ground operation in Gaza winding down, violence in a war that officials say has killed more than 1,880 Palestinians and over 60 Israelis appeared — for the moment — to be waning.