Zakaria Hamid Yahya Barbakh was shot dead on Monday near al-Awda Square in Rafah, south of Gaza.
Witnesses recorded the Israeli army firing at a man attempting to retrieve Barbakh's body.
Reports indicated another child had been killed, and nine others, including children, were injured by Israeli gunfire in Rafah earlier that day.
Palestinian sources claimed Israeli tanks breached a buffer zone, firing on civilians. The tanks advanced 850 meters into Gaza, exceeding the 700-meter limit set by the ceasefire agreement.
The ceasefire, effective since Sunday, is intended to last 42 days with negotiations for further phases mediated by Egypt, Qatar, and the United States. Hamas released three Israeli women in exchange for 90 Palestinian prisoners, mostly women and children, as part of the agreement.
Violence also escalated in the occupied West Bank, where Israeli settlers, backed by military forces, attacked villages north of al-Quds. Palestinian homes, a nursery, and a business were set ablaze.
The Office of the UN High Commissioner for Human Rights in Palestine expressed alarm over the "wave of renewed violence" by Israeli settlers and forces in the West Bank.
Israeli forces have set up military checkpoints and closed roads, restricting Palestinian movement across al-Khalil, Qalqilya, Salfit, and Bethlehem.
Meanwhile, US President Donald Trump signed an executive order reversing sanctions on Israeli settlers in the West Bank, previously imposed by the Joe Biden administration to counter the "extremist settlement movement."