Fallout continued Thursday from the deaths the day before of four cousins ages 9 to 11 who died in an Israeli military strike on a Gaza beach.

The results of a preliminary investigation suggests the deaths were the result of a "a tragic misidentification of the target," a spokesman for Israeli Prime Minister Benjamin Netanyahu told CNN on Thursday.

"We didn't want to kill those four boys. That was not our intention," Mark Regev said. "I'd even say the opposite is true. Had we known that that missile was aimed at four young men like that we would have not sent the missile."

A Hamas official called the killings a "war crime."

"Those children were not firing rockets, they were just playing," Hamas spokesman Sami Abu Zhuri told reporters Wednesday.

Regev, however, said a legitimate Hamas target was nearby, highlighting what he called a "complex combat environment" in crowded Gaza City and surrounding areas.

Israeli officials say militants often use mosques, schools and other crowded places to hide rockets and other weapons.

Indeed, the U.N. Relief and Works Agency said it had found 20 rockets hidden in a vacant school in Gaza, the first time the agency had made such a discovery.

The group didn't say who placed the rockets there but condemned the act as a "flagrant violation" of rules meant to keep U.N. aid workers safe.

For the hundreds of people gathered for the boys' funeral Wednesday, however, the legal and ethical arguments made little difference.

"I felt as if the world had come to an end when I heard the news," said Ramiz Bakr, the father of one of the boys. "I wish I had died before hearing he was dead."