GAZA CITY — The four Bakr boys were young cousins, the children of Gaza fishermen who had ordered them to stay indoors — and especially away from the beach. But cooped up for nine days during Israeli bombardments, the children defied their parents and went out Wednesday afternoon, the eldest shooing away his little brother, telling him it was too dangerous.

As they played on and around a jetty in the late-afternoon sun, a blast hit a nearby shack. One boy was killed instantly. The others ran. There was a second blast, and three more bodies littered the sand. One was charred, missing a leg, and another lay motionless, his curly head intact, his legs splayed at unnatural angles.

The Israeli military acknowledged later that it had launched the strike, which it said was aimed at Hamas militants, and called the civilian deaths “a tragic outcome.”

The four dead boys came quickly to symbolize how the Israeli aerial assaults in Gaza are inevitably killing innocents in this crowded, impoverished sliver of land along the Mediterranean Sea. They stood out because they were inarguably blameless, children who simply wanted to play on their favorite beach, near the fishing port where their large extended family keeps its boats.