UN Secretary-General Antonio Guterres is warning that Gaza is close to the brink of war and expressed his shock over the number of Palestinians killed and wounded by Israeli live fire during protests.
In a report on Monday, Mr Guterres told the Security Council that he "unequivocally condemns the steps by all parties that have brought us to this dangerous and fragile place" in the Israeli-Palestinian conflict.
The report was sent to the council last week before a meeting on Tuesday on the Israeli-Palestinian crisis.
The violence in Gaza marks the most serious escalation between Israel and Hamas since the 2014 war.
"It is and should be a warning to all how close to the brink of war the situation is," Mr Guterres said.
"I am shocked by the number of deaths and injuries of Palestinians resulting from the use of live fire by Israel Defence Forces" since protests began on March 30, he said.
At least 132 Palestinians have been killed. The Red Cross says more than 13,000 have been wounded, including 1,400 who suffered several gunshot wounds, many in the legs.
Israel has a responsibility to "exercise maximum restraint" and protect civilians in line with international humanitarian law, the UN chief wrote.
"The killing of children, as well as of clearly identified journalists and medical staffers, by security forces during a demonstration are particularly unacceptable," he added.
Two Palestinian journalists were killed while covering the protests in April, while a 21-year-old medic was shot dead in early June.
Mr Guterres renewed his call for an independent investigation of the shooting deaths in Gaza. Israel has rejected the appeal and argues that the use of force is justified to defend its borders.
The UN chief criticised Hamas and other militant groups for attempting to put explosives near the fence and for shooting rockets at Israel on May 29 and 30.
He singled out "senior Israeli government officials" for asserting that all Palestinians were affiliated with Hamas, signalling a "permissive Israeli policy towards the use of live fire against protesters".
Israel's settlement activities "continue unabated", Mr Guterres added, citing a May 30 decision by Israel to approve 3,500 housing units in the West Bank – the largest batch of new housing since June last year.
The UN considers the expansion of settlements on land earmarked for a future Palestinian state to be illegal. Mr Guterres said the construction must "cease immediately and completely".