GAZA CITY, Gaza Strip — Israel’s expanding ground and air offensive against Gaza’s Hamas rulers took a heavy civilian toll today, including three young brothers reported killed by a crashing shell and wounded who filled hospital corridors.

Diplomats and European leaders raced around the region in search of a cease-fire, but with Palestinian rocket fire continuing, Israel said it won’t stop its crippling 10-day assault until "peace and tranquility" are achieved in southern Israeli towns in the line of fire.