Palestinian and international groups have sharply criticized Israel for using live bullets against peaceful Palestinian demonstrators during “The Great March of Return” on the Gaza Strip border on Friday, killing four Palestinians, including Mohammed Ayoub, 15, who was killed by a bullet to the head. His death brought to 35 the number of Palestinians killed since border clashes intensified on March 30 in the ongoing protests that evoke a longtime call for Palestinians to regain ancestral homes in what is now Israel. For a month, clashes had erupted at the demonstrations and Israeli soldiers had used live fire to keep Palestinian crowds away from the border fence. On Friday, Ayoub had been among the thousands who gathered to protest, some of whom used catapults and sling-shots to launch stones at Israeli forces, hurled burning tires and tried to damage the fence. Israel’s use of live fire has drawn international criticism and Ayoub’s death received special attention. The European Union called on Israel on Saturday to investigate the death of Ayoub. "Yesterday Israeli soldiers again opened fire on protesters in Gaza using live ammunition from across the border fence killing four Palestinians, including a 15-year-old, and wounding more than 150. A full investigation is needed to understand what happened and why," said an EU spokesperson. The EU called on Israeli soldiers to refrain from using lethal force against unarmed protestors, reiterating the priority "to avoid any further escalation of violence and loss of life." Also, the United Nations Special Coordinator for the Middle East Peace Process Nickolay Mladenov condemned Israels killing of a Palestinian child. Writing on Twitter, Mladenov said: "It is OUTRAGEOUS to shoot at children! How does the killing of a child in #Gaza today help #peace? It doesn’t! It fuels anger and breeds more killing. #Children must be protected from #violence, not exposed to it, not killed! This tragic incident must be investigated." US Middle East envoy Jason Greenblatt put out his own tweet: “A full investigation by Israel of Mohammed Ayoub’s death is underway so that we will be able to understand what happened. As we mourn the tragic loss of a young life, we must all resolve to avoid causing more suffering by responses to his death.” Ayoub’s family said friends of their son told them he was not among stone throwers. Matthias Schmale, the Gaza director of operations of the United Nations Relief and Works Agency (UNRWA), which provides aid to over half of Gaza’s population, said Ayoub was the third student of UN-run schools to be killed in recent weeks. “Deeply disturbing news that child killed yesterday was yet another student at UNRWA school - two others were killed previously,” Schamale wrote on Twitter. “Children should never be targets.”