Patients with gunshot wounds filled wards and hallways in Gaza's under-equipped and overwhelmed main hospital on Tuesday, with dozens still waiting in line for surgery a day after Israeli soldiers shot and killed 59 Palestinians and wounded hundreds in mass protests on the Gaza border.
The high casualty toll triggered a diplomatic backlash against Israel and new charges of excessive use of force against unarmed protesters.
The UN Security Council began its session on Tuesday with a moment of silence for the dead, and the UN's special Mideast envoy said there was "no justification for the killing".
Turkey expelled Israel's ambassador, and several European countries called for an international investigation.
Nobel Peace Prize winner Archbishop Emeritus Desmond Tutu said he was "deeply distressed and broken-hearted by the massacre perpetrated" by Israel.
Growing despair
Israel said it has the right to protect its border and nearby communities, accusing Gaza's ruling militant group Hamas of carrying out several attacks under the guise of the protests.
The US ambassador to the UN, Nikki Haley, came to Israel's defence, saying no member "would act with more restraint than Israel has".
Monday's border confrontation was the culmination of a weeks-long protest campaign to break a border blockade that Israel and Egypt imposed after a Hamas took over Gaza by force in 2007.
The protests were led by Hamas, but fuelled by the growing despair among Gaza's two million people who face worsening poverty, unemployment, 22-hour-a-day power cuts and sweeping bans on travel and trade.
The protests were also driven by anger over the relocation on Monday of the US Embassy in Israel from Tel Aviv to contested Jerusalem. Palestinians seek Israeli-annexed east Jerusalem as a future capital.
Even before the latest round of bloodshed, Gaza's health system of 13 public hospitals and 14 clinics run by NGOs had buckled under persistent blockade-linked shortages of medicines and surgical supplies.
At Shifa Hospital in Gaza City, the main health facility in the strip, these woes were magnified this week.
Anticipating a major influx of casualties ahead of Monday's mass march, Shifa had set up an outdoor triage station under a green and blue tarp in the hospital courtyard, setting up 30 beds and stretchers there.
Gunshot wounds
Throughout the day Monday, Shifa received about 500 injured people, more than 90% with gunshot wounds, said hospital director Ayman Sahbani.
Of those, 192 needed surgery, including 120 who needed orthopaedic surgery, he said.
By mid-afternoon on Tuesday, overwhelmed surgeons working in 12 operating theatres had only performed 40 orthopaedic operations, with 80 others still waiting their turn.
In the orthopaedics department, nerves were frayed on Tuesday as relatives worried about wounded family members amid fears their conditions might deteriorate.
In one room, Ibrahim Ruhmi rested on a bed with bandages on both legs. He had been shot in the right leg, while shrapnel hit his left leg. Outside the room his mother was crying on a chair in the hallway, consoled by his 28-year-old sister, Faten.
Suddenly, the young woman started shouting at nurses in a burst of frustration.
"His leg will rot," she yelled. "What are you waiting for? Do you wait for it to rot so you can amputate it?"
A Hamas policeman, who was stationed as a security guard on the ward, tried to calm her down, to no avail.
"If you are unable to treat them, why are you letting them go to the protests," she said of her brother and the others who were wounded by Israeli snipers in the dangerous area near the border fence.
'Unfolding crisis'
Nickolay Mladenov, the special UN envoy to the region, told the Security Council on Tuesday that hospitals in Gaza were "reporting an unfolding crisis of essential medical supplies, drugs and equipment needed to treat the injured".
He said a UN official who visited Gaza, "witnessed first-hand patients being brought in on stretchers and left in the hospital's courtyard, which was being used as a triage area".
"There is no justification for the killing, there is no excuse," Mladenov said, adding that Israel had a responsibility to calibrate its use of force.
At the same time, he said, "messages by Hamas indicate the intention to use mass protests to infiltrate into Israel and attack Israelis".
On Monday, Israeli forces shot and killed 59 Palestinians and wounded more than 1 300, making it the deadliest single day in Gaza since a 2014 cross-border war between Israel and Hamas.
Two more Palestinians were shot dead in scattered border protests on Tuesday, bring the total since late March to more than 100, the Health Ministry said.
Israel's military said 14 of those killed on Monday were involved in planting explosives or firing on Israeli soldiers.
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