The White House says the deaths lie "squarely with Hamas" after Israeli troops fired at Palestinian protesters on the Gaza border.
Israeli forces have killed at least 58 Palestinians and left 2,771 injured during mass protests against the opening of the US embassy in Jerusalem, Palestinian health officials say.
The deaths include 57 adults and children who were shot and a baby who died from the effects of tear gas inhalation.
The bloodshed marks the deadliest day in the region since the 2014 Gaza war, with Israeli soldiers firing at protesters who had to flee for cover.
While both France and Britain called for restraint from Israel, the US blamed Hamas for the violence, with White House spokesperson Raj Shah saying the Palestinian group "is intentionally and cynically provoking this response".
The AP news agency reported that some Israeli forces had opened fire from tanks. Palestinians along the Gaza border had earlier hurled firebombs and stones towards troops.
Israel's military claimed its forces had come under fire during the clashes, adding that some protesters had tried to break through the fence.
It added that troops had shot and killed three Palestinians because they were trying to plant a bomb.
Dr Ashraf Al Qudra, the director of public relations for the Gaza ministry of health, said six children under 18 were among the dead and that 225 children and 79 women were among those injured
The UN Security Council will meet today to discuss the violence, but diplomats said members on Monday failed to come to unanimous agreement on a statement calling for restraint.
Palestinian president Mahmoud Abbas has condemned what he called Israeli "massacres" in Gaza.
The number killed climbed as the US embassy was opened 45 miles away in Jerusalem. The move comes after President Donald Trump recognised the city as Israel's capital in December 2017.
The relocation of the embassy from Tel Aviv, which was one of Mr Trump's key campaign promises, infuriated Palestinians who seek East Jerusalem as a future capital.
Israeli prime minister Benjamin Netanyahu addressed the crowd at the ceremony and thanked Mr Trump "for having the courage to keep your promises".
He added: "We are in Jerusalem and we are here to stay."
Commenting on the killings of Palestinians, he said Israel was acting in self defence against Hamas.
In a video message played during the inauguration, Mr Trump said he remains committed to "facilitating a lasting peace agreement" between Israelis and Palestinians.
His daughter Ivanka and her husband Jared Kushner attended the ceremony, leading a US delegation which included the treasury secretary and four Republican senators.
The White House has said the responsibility for the Gaza deaths "rests squarely with Hamas", the territory's ruling organisation which has been designated a terrorist group by the US and EU.
The clashes have raised doubts about Mr Trump's ambitions to broker what he once said would be the Middle East "deal of the century".
The Israeli military estimated a turnout of about 40,000 at the Palestinian protest on Monday, saying this fell short of what Hamas had hoped for.
The protests mark the culmination of a campaign led by Hamas to break the blockade of the territory imposed by Israel and Egypt since 2007.
Dozens of Palestinian protesters had already been killed by Israeli army fire in the weeks before the violence on Monday, with the marches having begun in late March 2018.
The timing of Monday's events was deeply symbolic both to Israel and the Palestinians.
The opening of the US embassy coincided with the 70th anniversary of Israel's founding.
But it also marks the anniversary of the "nakba", or catastrophe, when hundreds of thousands of Palestinians fled or were expelled from present-day Israel during the 1948 war.
Culled from Sky News.