JERUSALEM — Israeli forces killed 55 Palestinians on the Gaza border in the conflict’s bloodiest day in years on Monday as clashes and protests coincided with the deeply controversial opening of the US embassy in Jerusalem.

The unrest, which left more than 2,400 Palestinians wounded, erupted before a White House delegation and Israeli officials opened the embassy at an inauguration ceremony in Jerusalem.

It was the deadliest day in the Israeli-Palestinian conflict since the 2014 Gaza war.

The dead included eight children under the age of 16, according to the Palestinian envoy to the United Nations. The Gazan health ministry provided the overall death and injury toll.

Tens of thousands had gathered near the border in protest while smaller numbers of stone-throwing Palestinians approached the fence and sought to break through, with Israeli snipers positioned on the other side.

At the United Nations, the US blocked the adoption of a Security Council statement that would have called for an independent probe into the violence, diplomats said.

The embassy inauguration went on as planned, attended by a Washington delegation that included US President Donald Trump’s daughter Ivanka and her husband Jared Kushner, both White House aides.

Ivanka Trump helped declare the new embassy open and a plaque and seal were unveiled before the 800 guests at the ceremony, which took place at what until now had been a US consulate building in Jerusalem.

Trump addressed the gathering by video.

"Our greatest hope is for peace," he said, despite the Palestinian anger the move has provoked.

"The United States remains fully committed to facilitating a lasting peace agreement."

Israeli Prime Minister Benjamin Netanyahu told Trump in his address that "by recognising history you have made history".

Along the Gaza border, crowds built throughout the day in the Palestinian enclave less than 100 kilometres (60 miles) away from Jerusalem and sealed off from Israel by a blockade.

Israel’s military said 40,000 Palestinians had taken part in the protests and clashes.

The military also said one of its fighter jets had struck five targets at a Hamas training facility in Gaza.

Earlier, a warplane and tank targeted two other Hamas posts in response to what it said was fire toward its forces by Hamas.

Palestinian president Mahmud Abbas accused Israel of "massacres," while Amnesty International called the violence an "abhorrent violation" of human rights. Human Rights Watch denounced a "bloodbath".

EU foreign policy chief Federica Mogherini said "we expect all to act with utmost restraint to avoid further loss of life," while British Prime Minister Theresa May’s spokesman urged "calm and restraint".

Turkish President Recep Tayyip Erdogan accused Israel of "state terror" and "genocide", announcing three days of mourning and a giant protest in Istanbul on Friday. Turkey also said it was recalling its ambassadors to the US and Israel "for consultations". — AFP