At least 52 people have been killed during clashes Monday along the border fence between Israel and Gaza, according to the Palestinian Ministry of Health, and more than 2,400 people suffered injuries.
This is the biggest number of fatalities suffered in one day since the latest round of demonstrations began more than six weeks ago.
By a CNN count, based on Ministry of Health figures, more than one hundred people have been killed in the demonstrations since March 30.
The demonstrations were called to mark the official unveiling Monday of the new US Embassy in Jerusalem, which has been relocated from Tel Aviv in a controversial move that has been praised by Israelis but has enraged Palestinians.
Most of the dead were killed by Israeli fire near the border. CNN journalists there heard gunfire in spurts and saw a tank moving towards the fence in the border area of Malaka. Israeli drones also dropped tear gas over a crowd of protesters.
The Palestinian Health Ministry said more than 1,600 had suffered injuries, and that many of the dead had not yet been identified.
The Israel Defense Forces (IDF) released a statement Monday accusing the Palestinian militant group Hamas, which controls Gaza, of "leading a terrorist operation" and inciting protesters who had amassed by the border fence with Israel to conduct what Israel described as terror attacks.
The IDF estimated that around 35,000 people -- who it describes as "violent rioters" -- had assembled in 12 different locations along the border fence between Gaza and Israel and thousands more were gathered in a tent city about a kilometer from the border.
The military said the protesters threw Molotov cocktails, burned tires, and stones at Israeli soldiers positioned along the fence. The IDF also says it foiled an attack by three armed Palestinians near Rafah, close to the border with Egypt, during "a particularly violent demonstration."
The Palestinian Health Ministry said 443 injuries were caused by live ammunition, 320 by tear gas, and three by rubber-coated bullets.
The first victim to be named was Anas Hamdan Qdeih, a 21-year-old, who was shot dead by Israeli forces east of Khan Younis, according to the Palestinian Health Ministry.
Earlier, the Israeli army air-dropped leaflets over Gaza warning people not to approach the fence that separates Gaza from Israel.
More than 90 people have been killed by Israeli soldiers since the latest wave of protests began in March, according to a CNN count based on the Palestinian Ministry of Health figures.
Demonstrators say they want to highlight their right to return to homes lost by their ancestors during the war that accompanied the founding of the state of Israel in 1948.
Israel says the demonstrations are orchestrated by Hamas and has insisted its forces are acting "according to standard operating procedures."
What is going on in Gaza?
Palestinians have held weekly protests there in the run-up to their annual commemoration of what they call the Nakba or Catastrophe, when hundreds of thousands of their people fled their homes or were displaced following the foundation of the Israeli state on 14 May, 1948.
Scores of Palestinians have been killed since the protests began. Thousands more have been wounded.
Hamas, which is in a state of conflict with Israel, had said it would step up protests in the lead-up to Tuesday, the official Nakba commemoration.
It says it wants to draw attention to what Palestinians insist is their right to return to ancestral homes in what became Israel.
"Today is the big day when we will cross the fence and tell Israel and the world we will not accept being occupied forever," a science teacher in Gaza, Ali, told Reuters news agency.
Israel says the protests are aimed at breaching the border, which it guards heavily, and attacking Israeli communities nearby.
The Israeli military said it had killed three people trying to plant explosives near the security fence in Rafah.
Why is the embassy move so controversial?
The status of Jerusalem goes to the heart of the Israeli-Palestinian conflict.
Israeli sovereignty over Jerusalem is not recognised internationally and, according to the 1993 Israel-Palestinian peace accords, the final status of Jerusalem is meant to be discussed in the latter stages of peace talks.
Israel has occupied East Jerusalem since the 1967 Middle East war. It effectively annexed the sector, though this was not recognised by any countries until Trump's declaration in December 2017.
Since 1967, Israel has built a dozen settlements, home to about 200,000 Jews, in East Jerusalem. These are considered illegal under international law, although Israel disputes this.
Various countries once had embassies based in Jerusalem but many moved after Israel passed a law in 1980 formally making Jerusalem its capital.
President Trump's decision last year to recognise Jerusalem as Israel's capital broke with decades of US neutrality on the issue and put it at odds with most of the international community.
A boost for Netanyahu
The embassy move is the culmination of one of the best weeks in the political life of Israel's Prime Minister, Benjamin Netanyahu.
First President Trump kept his promise to pull out of the Iran nuclear deal. Now the US embassy is moving.
Placards in Jerusalem praise Trump. The local football club, Beitar, infamous for fans who chant "death to Arabs", has included "Trump" in its name.
The embassy move has been rejected by the main allies of Israel and the US. Palestinians are protesting in their thousands in Gaza.
It is much more low-key in the West Bank, including occupied East Jerusalem.
The embassy move is good for the Netanyahu government, good for President Trump's base and makes most Israelis pleased but there is no evidence to back Netanyahu's claim that it is good for peace.
What will be opened and who will attend?
A small interim embassy will start operating on Monday inside the existing US consulate building in Jerusalem.
A larger site will be found later when the rest of the embassy moves from Tel Aviv.
The opening ceremony was brought forward to coincide with the state of Israel's 70th anniversary.
President Trump is expected to address those attending Monday's event via video link. In a tweet, he said it was "a great day for Israel".
Alongside Ivanka Trump and Jared Kushner, who are both senior White House advisers, Treasury Secretary Steven Mnuchin and Deputy Secretary of State John Sullivan will be at the ceremony.
The EU has voiced strong objections to the embassy move.
The decision to recognise Israel as Jerusalem's capital and move the embassy is strongly supported by Israeli Jews across the often fractious political spectrum.
Palestinian Authority President Mahmoud Abbas, however, has described Trump's decision as the "slap of the century". He says the US can no longer be considered a neutral broker in on-off Israeli-Palestinian peace talks and cannot have any future role.
Sources: CNN, BBC