Updated

The Trump administration officially opened the new U.S. Embassy in Jerusalem on Monday, in a historic move cheered by Israelis but met with mass protests from Palestinians that turned deadly in the lead-up to the ceremony.

Clashes at the border had left dozens of Palestinians dead and hundreds wounded by the time the ceremony ended. But Israel's prime minister praised the Israeli security forces for protecting the Gaza-Israel border, as U.S. officials held out hope that the prospect of peace is still in reach.

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U.S. Treasury Secretary Steven Mnuchin and Ivanka Trump, left, among others, unveil the U.S. Embassy in Jerusalem. (Ronen Zvulun)

In a video address moments before his daughter Ivanka unveiled the embassy plaque with Treasury Secretary Steven Mnuchin, President Trump touted the embassy opening as a “testament to the unbreakable spirit of the Jewish people.”

In moving the embassy from Tel Aviv to the holy city -- a relocation long debated in Washington -- Trump said America was simply recognizing reality.

"For many years, we have failed to acknowledge the obvious, plain reality that the [Israeli] capital is Jerusalem. At my direction, the United States finally and officially recognized Jerusalem as the true capital of Israel," Trump said.

The relocation fulfills a key campaign promise of the president and makes good on Trump's recognition of Jerusalem as Israel's capital just months ago. To mark the occasion, the Trump administration sent a huge delegation including Ivanka Trump, son-in-law and senior adviser Jared Kushner, Mnuchin, U.S. Ambassador to Israel David Friedman, and Deputy Secretary of State John J. Sullivan.

“The United States will always be a great friend of Israel and a partner in the cause of peace,” Trump said in his video address. “We extend a hand in friendship to Israel, the Palestinians and to all of their neighbors. May there be peace.”

Israeli Prime Minister Benjamin Netanyahu expressed how “deeply grateful” he and the Israeli people are to the U.S.

“President Trump, by recognizing history, you have made history,” Netanyahu said Monday, reminiscing on his childhood, when he was forbidden to run too close to Jerusalem. “My mother said you can’t go any farther, that was near the border. There was sniper fire. That was then—this is now. Today the embassy of the most powerful nation on earth, our greatest ally, the United States of America, today the United States Embassy opened here. What a difference.”

Netanyahu added that it was a “great day for Israel," for the U.S.-Israel alliance and for peace.

"We are in Jerusalem and we are here to stay," Netanyahu said.

But Palestinians, who claim east Jerusalem as the capital of a future state, vehemently oppose the relocation. Weekslong protests flared to new levels of violence in the hours before the ceremony at spots along the Gaza-Israeli border.

Netanyahu referenced the clashes during his remarks, praising the “brave soldiers protecting” the borders.

But the violence threatened to overshadow the jubilant ceremonies in Jerusalem. At least 52 Palestinians were killed and 900 wounded, Palestinian health officials said, as Israeli security forces fired on a surge of protesters at the border, vowing to prevent a breach. It marked the deadliest day since the Hamas-led border protests began in March.

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Ivanka Trump and Treasury Secretary Steven Mnuchin at the opening of the U.S. Embassy in Jerusalem. (AP)

Earlier Monday, Mnuchin said the Trump administration’s decision to relocate the Israel embassy from Tel Aviv to Jerusalem is a “national security priority” for the U.S.

Kushner, also a senior White House adviser, said that the sitting president has "delivered" where previous presidents "backed down."

“We believe, it is possible for both sides to gain more than they give – so that all people can live in peace – safe from danger, free from fear, and able to pursue their dreams,” he said.

He added: “Jerusalem must remain a city that brings people of all faiths together.”

Israel prepared enthusiastically Sunday for the formal embassy opening with a gala party at its Foreign Ministry that included Ivanka Trump, Kushner and other U.S. officials.

Netanyahu told revelers that Trump's December declaration recognizing Jerusalem as Israel's capital was "the right thing to do."

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President Trump said in prepared video remarks that the U.S. "finally and officially recognizes Jerusalem as the capital of Israel." (AP)

The prime minister said Trump's decision recognized a 3,000-year Jewish connection to Jerusalem and the "truth" that Jerusalem would be Israel's capital under any future peace deal.

Meanwhile, Israel bolstered its border security as thousands of Gaza residents amassed at the Israeli border. Since weekly border marches began in late March, dozens of Palestinian protesters have been killed and more than 2,000 wounded by Israeli army fire.

Hamas leaders have suggested a possible border breach in the days leading up to the embassy celebration, while Israel has warned it would prevent protesters from breaking the border at any cost.

Palestinian officials have criticized the Trump administration for its decision to move the U.S. Embassy to Jerusalem. Palestinian President Mahmoud Abbas cut ties with the U.S., declaring it unfit to be the sole mediator for potential peace between Israel and Palestine.

The Trump administration had brushed off Palestinian criticism, saying that the embassy move could be a first step for brokering a peace agreement.

Fox News’ Ryan Gaydos, Samuel Chamberlain and the Associated Press contributed to this report.