GAZA, Palestinian Territory -- In a jarring contrast, Israeli forces shot and killed at least 55 Palestinians and wounded more than 1,200 during mass protests Monday along the Gaza border, while just a few miles away Israel and the U.S. held a festive inauguration ceremony for the new American Embassy in contested Jerusalem.

It was by far the deadliest day of cross-border violence since a devastating 2014 war between Israel and Gaza's Hamas rulers, and further dimmed the already bleak prospects for President Donald Trump's hoped-for peace plan.

Throughout the day, Gaza protesters set tires ablaze, sending thick plumes of black smoke into the air, and hurled firebombs and stones toward Israeli troops across the border. The Israeli military, which has come under international criticism for using excessive force against unarmed protesters, said Hamas tried to carry out bombing and shooting attacks under the cover of the protests and released video of protesters ripping away parts of the barbed-wire border fence.

Monday's protests culminated more than a month of weekly demonstrations aimed at breaking a crippling Israeli-Egyptian border blockade. But the U.S. Embassy move, bitterly opposed by the Palestinians, added further fuel.

There was barely any mention of the Gaza violence at Monday's lavish inauguration ceremony for the new embassy, an upgraded consular building located just 50 miles (80 kilometres) away. Israeli Prime Minister Benjamin Netanyahu and other top officials joined an American delegation of Trump administration officials and Republican and evangelical Christian supporters.

Jared Kushner, Trump's son-in-law and chief Mideast adviser, headlined the U.S. delegation with his wife and fellow White House adviser, Ivanka Trump, as well as Treasury Secretary Steven Mnuchin and four Republican senators. Republican super-donor Sheldon Adelson was also present, and evangelical pastors Robert Jeffress and John Hagee delivered blessings.

"A great day for Israel!" Trump tweeted earlier Monday.

In a videotaped address, Trump said the embassy move, a key campaign promise, recognizes the "plain reality" that Jerusalem is Israel's capital. Yet he added the United States "remains fully committed to facilitating a lasting peace agreement."

But Monday's steadily climbing death toll and wall-to-wall condemnation of the embassy move in the Arab world raised new doubts about Trump's ambitions to broker what he called the "deal of the century." More than a year after taking office, Trump's Mideast team has yet to produce a long-promised peace plan.

Trump says recognizing Jerusalem as Israel's capital acknowledges the reality that Israel's government is located there as well as the ancient Jewish connection to the city. He insists the decision has no impact on future negotiations on the city's final borders.

But to both Israel and the Palestinians, the American gesture is widely seen as siding with Israel on the most sensitive issue in their longstanding conflict.

"What a glorious day. Remember this moment. This is history," Netanyahu told the inauguration ceremony.

"You can only build peace on truth, and the truth is that Jerusalem has been and will always be the capital of the Jewish people, the capital of the Jewish state," he added.

The Palestinians, who seek east Jerusalem as their capital, have cut off ties with the Trump administration and say the U.S. is unfit to serve as a mediator. Israel captured east Jerusalem in the 1967 Mideast war and annexed the area in a move that is not internationally recognized.

Palestinian President Mahmoud Abbas, furious over the embassy ceremony, said he "will not accept" any peace deal proposed by the Trump administration.

The Palestinian president also urged the international community to condemn what he said were "massacres" carried out by Israeli troops in Gaza, and officials said the Palestinians would file a war crimes complaint against Israel in the International Criminal Court over settlement construction.

By nightfall, at least 55 Palestinians, including a young girl and four other minors, were killed, the Gaza Health Ministry said. It said 1,204 Palestinians were wounded by gunfire, including 116 who were in serious or critical condition.

Egypt, an important Israeli ally, condemned the killings of Palestinian protesters, while the U.N. human rights chief, Zeid Ra'ad al-Hussein, decried the "shocking killing of dozens."

Turkey said it was recalling its ambassador to the United States over the U.S. Embassy move, saying it "disregarded the legitimate rights of the Palestinian people" and would "not serve peace, security and stability in the region." It also recalled its ambassador to Israel following what it called a "massacre" of Palestinians on the Gaza border.

South Africa, a fervent supporter of the Palestinians, also recalled its ambassador for consultations, the Israeli Foreign Ministry said.

The European Union's foreign policy chief, Federica Mogherini, called on Israel to respect the "principle of proportionality in the use of force" and show restraint, while also urging Hamas to ensure any protests remain peaceful. U.N. Secretary-General Antonio Guterres issued a similar appeal.

At the U.S. Embassy ceremony in Jerusalem, Kushner placed the blame on the Gaza protesters.

"As we have seen from the protests of the last month and even today those provoking violence are part of the problem and not part of the solution," he said.

Israel says the blockade of Gaza, imposed by Israel and Egypt after Hamas overran the territory in 2007, is needed to prevent Hamas from building up its military capabilities. But it has decimated Gaza's economy, sending unemployment skyrocketing to over 40 per cent and leaving the territory with just a few hours of electricity a day.

The Israeli military estimated a turnout of about 40,000 at Monday's protest, saying it fell short of what Hamas had hoped for. But officials described what they called "unprecedented violence" unseen in previous weeks.

Lt. Col. Jonathan Conricus, a military spokesman, said hundreds of protesters carried out "concerted, co-ordinated" attacks on the border fence.

Although the crowd did not manage to break through, he said they caused "significant damage." The army released video showing demonstrators setting a cargo crossing on fire and appearing to climb on the fence as they lobbed flaming objects into the Israeli side.

Conricus also said Hamas militants disguised as protesters tried to infiltrate, and there were at least three instances of armed Hamas gunmen trying to carry out attacks. Israeli aircraft and tanks struck seven Hamas positions.

Monday marked the biggest showdown in years between Israel's military and Gaza's Hamas rulers along the volatile border. The sides have largely observed a cease-fire since the 2014 war -- their third in a decade.

Since the protests began on March 30, 105 Palestinians have been killed, most of them protesters. Israel said it killed three militants trying to plant a bomb along the fence, and Palestinian security officials said several Hamas militants were also killed by Israeli shelling in northern Gaza.

Ismail Radwan, a senior Hamas figure, said the mass border protests would continue "until the rights of the Palestinian people are achieved."

Throughout the day, sirens wailed as the wounded were carried to ambulances. Groups of young activists repeatedly approached the fence, but were quickly scattered by gunfire and tear gas.

The timing of Monday's events was deeply symbolic to Israel and the Palestinians.

The U.S. said it chose the date to coincide with the 70th anniversary of Israel's establishment.

But Tuesday also marks the anniversary of what Palestinians call their "nakba," or catastrophe, a reference to the uprooting of hundreds of thousands who fled or were expelled during the 1948 war surrounding Israel's creation. A day of mourning and mass funerals was planned Tuesday.

A majority of Gaza's 2 million people are descendants of refugees, and the protests have been billed as the "Great March of Return" to long-lost homes in what is now Israel.

The new embassy will temporarily operate from an upgraded, existing U.S. consulate building, until a decision is made on a permanent location. Even the current location is sensitive, located partially in an area designated "no-man's land" in a 1949 armistice agreement. The U.N. considers that land to be occupied territory, though the U.S. says in practice the area has been in continuous Israeli use since 1949.

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Federman reported from Jerusalem. Associated Press writers Ilan Ben Zion in Mefalsim, Israel, Mohammed Daraghmeh in Ramallah, West Bank, and Karin Laub in Amman, Jordan, contributed to this report.