Some 58 Palestinians were killed on Monday, including six children, by Israeli forces
A UN human rights expert has called on the Israeli government to "immediately cease its lethal assault" against protesters at the Gaza fence.
Michael Lynk, the special rapporteur on the situation of human rights in the Palestinian territory occupied since 1967, said the prosteters "appear to pose no credible threat to Israeli military forces on the Israeli side of the fence."
He has condemned Israel's excessive use of force towards "largely unarmed demonstrators" at the Gaza fence on Monday, which has left 58 Palestinians dead, and almost 2,800 wounded.
Palestinian officials reported that at least 2,771 people were injured, including 1,359 by live ammunition.
Mr Lynk also expressed fears this figure could rise sharply in coming days, unless Israeli authorities uphold their obligations under international human rights law and international humanitarian law.
He said: "This blatant excessive use of force by Israel - an eye for an eyelash - must end, and there must be true accountability for those in military and political command who have ordered or allowed this force to be once again employed at the Gaza fence.
"I must reiterate that international human rights law sets strict prohibitions on the use of force by law enforcement officials.
"Lethal force against demonstrators is prohibited unless strictly unavoidable in the case of an imminent threat to life or threat of serious injury.
"The killing of demonstrators in violation of these rules, and within the context of occupation, may amount to willful killing, a grave breach of the Fourth Geneva Convention, as well as a war crime."
Mr Lynk also expressed deep concern at the apparent disregard by Israeli forces for the rights to freedom of expression and assembly.
"These fundamental rights belong to all peoples, and they must be permitted to exercise them within reasonable bounds.
"There appears to be no persuasive evidence that the use of flammable kites, throwing of stones or Molotov cocktails, or other actions reportedly taken by a small number of the demonstrators presented a deadly threat that justified the force used by the Israeli military."
Tens of thousands of Gazans have gathered along the fence and continue to demonstrate to protest the opening of the US embassy in Jerusalem, as well as to continue to call for the right to return to their homes, and demand an end to Israel's 11-year blockade.
The Committee to Protect Journalists (CPJ) also said gunfire was used against journalists covering the protests on Monday in the Gaza Strip.
At least seven Palestinian journalists were injured by Israeli gunfire while covering the demonstrations.
That is according to the Palestinian Journalists Syndicate (PJS), reports shared on social media by media outlets and journalists, and CPJ interviews with local journalists Saud Abu Ramadan and Moneeb Saada.
Thousands of Palestinians have been protesting for seven consecutive weeks over Israel's refusal to allow Palestinian refugees to return to their pre-1948 homes.
Since the protests began, the CPJ has documented that live rounds fired by the Israeli Defence Forces have hit at least 22 journalists.
Two of these people - Yaser Murtaja and Ahmed Abu Hussein - later died from their injuries.
The violence on Monday marked the deadliest day in the region since the Gaza war in 2014, and marked a dramatic escalation after weeks of protests.
The latest reports say that 112 Palestinians have been killed and more than 12,000 wounded since the demonstrations began on March 30th.