Four Palestinians were killed and hundreds wounded in a fifth round of weekly protests along the Gaza Strip border fence with Israel.Gaza’s Health Ministry said Saturday that 15-year-old Azzam Oweida, who was hit in the head by a gas canister fired by the IDF during Friday’s protest, died from his wounds.According to the ministry, his death brought the number of Palestinians killed by Israeli fire since the start of the “Great March of Return” to 45, with more than 1,500 wounded. No Israeli has been injured.The IDF said about 10,000 people had taken part in the “violent riots” along the border, with troops responding with riot dispersal means. The IDF holds that it only opens fire at “main instigators” and demonstrators who engage in violence by throwing stones or Molotov cocktails toward troops or those who attempt to breach the fence.The army said it had thwarted an infiltration at the old Karni Crossing in northeastern Gaza by “hundreds of rioters” who tried to burn the fence. The crowd had thrown explosive devices, firebombs and rocks leading troops to open fire “in accordance to the rules of engagement.”Late Friday, the Israel Air Force struck six Hamas naval commando targets in the Port of Gaza in response to the infiltration attempt.“The IDF considers with the utmost gravity the continued attempts by the Hamas terror organization to transform the fence zone into an area of violence and terror,” it said. “The response to similar incidents will not be confined to the area of the border fence, and the Hamas terror organization will bear responsibility for the consequences even deep inside the Gaza Strip.”The IDF accuses Hamas of using the protests as a cover to carry out attacks against its troops.According to local Palestinian media, the strikes targeted boats that were preparing to receive supplies for the demonstrations.Ahead of the protests, UN Special Coordinator for the Middle East Peace Process Nikolay Mladenov urged Israel and Hamas to refrain from violence.“There has also been an increasing number of dangerous incidents at the fence, including the planting of improvised explosive devices – at least one of which has detonated – the throwing of Molotov cocktails and attempts to breach the fence,” he said.“Israel must calibrate its use of force and minimize the use of live fire. Hamas must keep protesters away from the fence and prevent violent actions and provocations. Children, who should be particularly protected, are at grave risk.”While Friday’s demonstrations were violent, security officials have noticed a marked decline since the first week of rioting, which saw 30,000 Gazans take part. The past two weeks have only seen a third of that.UN High Commissioner for Human Rights Zeid Ra’ad al-Hussein said Friday that Israel must stop the excessive use of force and must hold accountable those responsible for the many deaths and wounds sustained by Palestinians in the past month.“The loss of life is deplorable, and the staggering number of injuries caused by live ammunition only confirms the sense that excessive force has been used against demonstrators – not once, not twice, but repeatedly,” he said.International law permits the use of lethal force in cases of “extreme necessity” but it was hard to see how stones or Molotov cocktails thrown from a great distance at heavily protected security forces could constitute such a threat, Zeid said.Reuters contributed to this report.