Gaza (CNN) Israeli forces killed dozens of Palestinians in bloody clashes at the Gaza border Monday in the deadliest day there since the 2014 war, as the US officially opened its Embassy in Jerusalem just 50 miles away.
At least 58 Palestinians died, according to the Palestinian Health Ministry, during protests over the Trump administration's controversial relocation of the Embassy from Tel Aviv, a 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 heard gunshots in spurts and saw a tank moving towards the fence in the border area of Malaka. Israeli drones also dropped tear gas in an effort to disperse protesters.
Palestinian officials accused Israel of committing a "horrific massacre" and called on the international community to immediately intervene. The Palestinian Health Ministry said more than 2,700 had suffered injuries, and that many of the dead had not yet been identified.
In a statement, the Israel Defense Forces (IDF) accused the Palestinian militant group Hamas, which controls Gaza, of "leading a terrorist operation" and inciting around 35,000 protesters who had assembled in numerous locations along the border fence to conduct what Israel described as terror attacks.
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."
Many of the injured Palestinians were young men who were hit by live ammunition, according to British-Palestinian doctor Ghassan Abu Sitteh, who spoke to CNN from a hospital run by a British charity in Jabaliya camp in northern Gaza.
Monday's death toll was the biggest number of fatalities suffered in one day since the latest round of demonstrations began more than six weeks ago. The previous high was 17, which happened on the day the protests started on March 30.
"By far, this is the worst day. Worse than the first Friday (of the Gaza protests) and we're expecting it to be as bad tomorrow," Abu Sitteh said, adding that a majority of the wounded were suffering from limb injuries that could have "long-term consequences."
"Each of these young men will need five or seven surgeries for their injuries and I would say 60% of them will be left with some permanent disability."
Israeli Prime Minister Benjamin Netanyahu defended the military's actions, tweeting Monday evening that "every country has the duty to defend its borders."
Netanyahu concluded security consultations with the defense minister, public security minister, IDF chief of staff, and others on Monday night, ahead of more expected protests.
In a statement from the Prime Minister's office, Netanyahu noted that "the determined action of the IDF and the security forces prevented a breach into Israel's borders."
More widespread protests are expected on Tuesday, when Palestinians mark Nakba Day, during which they mourn what they consider the "catastrophe" of the creation of the state of Israel 70 years ago.
Palestinian Authority President Mahmoud Abbas convened an emergency government meeting on Monday afternoon and announced a general strike and three days of mourning, both to start Tuesday.
"Today is one of the most ferocious days our people have seen," Abbas said, before turning his thoughts to the newly-anointed US Embassy. "Before we were suffering from illegal Israeli settlements. Now it's another illegal settlement by the Israel and the United States."
Turkey is recalling its ambassadors to Washington and Tel Aviv for consultations, according to state-run Anadolu Agency, citing Deputy Prime Minister Bekir Bozdag. Separately, Turkey Prime Minister Recep Tayyip Erdogan, while speaking in London, called Israel "a terrorist state" and said "what Israel is doing is a genocide," Anadolu reported.
The Saudi Ministry of Foreign Affairs expressed its "strong condemnation" of the use of force by Israel against Palestinian civilians that led to dozens of deaths and injuries, the official Saudi press agency said. "It is important for the international community to know its responsibilities towards stopping the violence against Palestinians and protecting them," a Saudi foreign ministry official said, according to the SPA.
United Nations Secretary-General António Guterres was "profoundly alarmed" by the violence in Gaza and urged Israeli forces to "exercise maximum restraint in the use of live fire," his deputy spokesman Farhan Haq said.
"The responsibility for these tragic deaths rests squarely with Hamas," White House deputy press secretary Raj Shah said. "Hamas is intentionally and cynically provoking this response and as the secretary of state (Mike Pompeo) said, Israel has a right to defend itself."
On Monday, a proposed UN Security Council press statement on the developments in the Palestinian territory and ongoing protests in the Gaza Strip was blocked by the US, according to a UN diplomat. Another UN diplomat provided CNN with the proposed statement, which the diplomat said was offered to Security Council members by Kuwait.
"The Security Council expresses its outrage and sorrow at the killing of Palestinian civilians exercising their right to peaceful protest," the draft press statement said.
Kuwait also requested an urgent United Nations Security Council meeting on the situation in the Middle East and Gaza for Tuesday morning. The UN's special coordinator for the Middle East Peace Process was expected to brief the Security Council on the situation Tuesday, UK Ambassador Karen Pierce told reporters Monday afternoon.
Several top Trump administration officials were on hand to witness the official unveiling of the US Embassy in Jerusalem on Monday, marking the formal upending of decades of American foreign policy.
President Donald Trump did not attend the ceremony, but in a video message broadcast at the event he congratulated Israel, saying the opening had been "a long time coming."
"Israel is a sovereign nation with the right like every other sovereign nation to determine its own capital, yet for many years, we failed to acknowledge the obvious, the plain reality that Israel's capital is Jerusalem," Trump said in the pre-recorded remarks.
Politicians and dignitaries, including Ivanka Trump and her husband Jared Kushner, watched as US Treasury Secretary Steve Mnuchin unveiled the US seal, turning what was formally the consulate building into the Embassy.
Speaking at the ceremony, Netanyahu hailed the alliance between America and Israel as "stronger than ever," and described Monday as "a day that will be engraved in our national memory for generations."
The Embassy move is contentious for Palestinians, who hope to claim part of Jerusalem as their future capital, and for many in the Arab world, as it is home to some of the holiest sites in Islam. The city is also home to deeply holy sites for Jews and Christians.
While Monday's protests in Gaza were organized to coincide with the Embassy opening, the demonstrations are about far more than the change in status of the US consulate building in Jerusalem.
On every Friday since the end of March, tens of thousands have marched to the border to take part in "Great March of Return" protests, which seek to highlight Palestinians' right to return to homes lost by their ancestors during the war that accompanied the founding of the state of Israel in 1948.
The protests culminate on Tuesday with the anniversary of what Palestinians call Nakba Day, or "Day of Catastrophe," which marks the more than 700,000 Palestinians who were either expelled from or fled their homes during the wars that surrounded Israel's foundation. Thousands are expected to attend Tuesday's demonstration.
More than 100 Palestinians have been killed during seven weeks of protests, with more than half of the deaths coming on Monday, according to a CNN count based on Palestinian Health Ministry figures.
Criticism of Israel has come from a range of nations and groups, from Egypt to the Israeli peace group B'Tselem. The United Nations anti-racism committee also called on Israel to end "disproportionate use of force" against the protesters Monday. Amnesty International has also criticized what it described as a "shameless violation of international laws, in some instances committing what appear to be willful killings constituting war crimes."