They were supposed to be safe.

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Bahaa Abu al-Ajeen was walking his 3-year-old son, Rayan, back to the tarpaulin-covered shack they called home, a makeshift dwelling providing some shelter from the sun on a war-ruined farm in central Gaza.

The pair walked in what was designated as a safe area for civilians close to the “yellow line,” a boundary marked with yellow blocks and flags that divides Palestinian-controlled parts of Gaza from areas under Israeli military control. But al-Ajeen, 38, said that as they were confronted by Israeli soldiers, he froze.

“At that moment, I did not know whether to move forward or backward,” he said. As Rayan began screaming, al-Ajeen, whose family has long farmed in the area, picked up his son and began walking again.

That’s when the soldiers fired what the Israeli military later described as “warning” shots.

The third shot struck Rayan in the head, al-Ajeen told NBC News from al-Aqsa Hospital on June 15, a day after the incident. “After that, they shot at me, as well.”

Al-Ajeen tried to call for an ambulance, but, he said, the soldiers took his phone and dragged him beyond the yellow line, still carrying Rayan, who was bleeding on his chest.

“I told them: ‘The child is dying. You killed him in cold blood,’” he said. “‘What has this child done wrong?’”

“No medical assistance whatsoever” was provided to his dying son, he said, and it was hours in detention before the gunshot wound to his own leg was treated.

Rayan’s death is the latest in a series of child killings feeding scrutiny over Israel’s treatment of Palestinian children. A United Nations report this month alleged that Israel has deliberately targeted children, resulting in genocide, crimes against humanity and war crimes in the occupied West Bank and Gaza Strip, where shifting military boundaries have blurred the line between combat zones and protected civilian space.

The commission of inquiry said it has reasonable grounds to conclude that the acts “form part of a deliberate strategy to destroy the future of the Palestinians in Gaza by targeting their children.” Israel has strongly rejected the findings.

Asked about al-Ajeen’s case, the Israel Defense Forces said in a statement June 16 that troops had identified “several Gazans approaching them” as they carried out activity in the yellow-line area in central Gaza on June 14. They said the troops “initiated standard suspect apprehension procedures, which included warning fire.”

“It was reported that, as a result of the fire, one Gazan was killed and another was injured,” the IDF said, adding that the details were under review. Asked to confirm whether a child was killed, as well as how close those who were fired upon were to Israeli forces and whether the yellow line was visibly marked, the IDF said it had no further comment.