Palestinians were gathering Tuesday for fresh protests along the Gaza border, a day after Israeli forces killed dozens there as the US embassy opened in Jerusalem on what was the conflict's bloodiest day in years.

Palestinians on Tuesday marked the Nakba, or "catastrophe", commemorating the more than 700,000 Palestinians who fled or were expelled in the 1948 war surrounding Israel's creation.

It came a day after the United States transferred its Israel embassy from Tel Aviv to the disputed city of Jerusalem in a move that infuriated the Palestinians and was widely condemned.

Most of the 60 Gazans killed Monday were shot by Israeli snipers, Gaza's health ministry said.

The toll included a baby who died from tear gas inhalation along with eight children under the age of 16, the ministry said.

At least 2,400 others were wounded in the bloodiest day in the Israeli-Palestinian conflict since the 2014 Gaza war.

Some funerals were held on Monday, while others were taking place Tuesday.

Hundreds of people took part in the funeral of Yazan Tubasi, 23, killed east of Gaza City.

His father Ibrahim, 50, said his son had a boy aged one year and three months.

"I am happy that my son is a martyr," he said, though he was crying uncontrollably. "He is among dozens who died for the sake of Palestine and Jerusalem."

Small numbers of protesters began returning to the border area on Tuesday, with larger crowds expected later.

In the West Bank, Palestinian president Mahmud Abbas declared a general strike on Tuesday after accusing Israel of "massacres".

- Protests and clashes -

On Monday, 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.

The death toll led to strong condemnation from rights groups and concern from a range of countries.

But the United States, which blamed Hamas, blocked the adoption of a UN Security Council statement that would have called for an independent probe into the violence, diplomats said.

Despite the bloodshed, the embassy inauguration went ahead as planned in Jerusalem, attended by a Washington delegation that included US President Donald Trump's daughter Ivanka and her husband Jared Kushner, both White House aides.

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

It said its aircraft had targeted 11 Hamas sites and tanks fired at "two terror posts belonging to Hamas", accusing the Palestinian Islamist movement of opening fire towards Israeli forces.

Israel says its action is necessary to stop infiltrations of the border fence and claims that Hamas, which runs the blockaded Gaza Strip, uses the protests as cover to carry out violence.

But French President Emmanuel Macron condemned the "violence of the Israeli armed forces against the protesters" while EU foreign policy chief Federica Mogherini said "we expect all to act with utmost restraint to avoid further loss of life".

Britain's minister for the Middle East, Alistair Burt, acknowledged "Israel's right to defend its borders" but also said "the large volume of live fire is extremely concerning".

"We continue to implore Israel to show greater restraint," he said.

Turkish President Recep Tayyip Erdogan accused Israel of "state terror" and "genocide".

Turkey also said it was recalling its ambassadors to the United States and Israel "for consultations", while South Africa recalled its ambassador to Israel "until further notice".

In Dublin, Ireland summoned Israel's ambassador to protest.

The UN rights office said it seemed any Palestinian protesting in Gaza, regardless of whether they pose an imminent threat, is "liable" to be killed by Israeli forces.

China called for restraint, "especially" from Israel.

- 'Rioters' at the border -

At least 114 Palestinians have been killed in a campaign of protests along the Gaza border since March 30, the vast majority by Israeli snipers during clashes.

Only one Israeli soldier has been reported wounded during that time.

On Monday, the army said "many rioters" tried to breach the border fence and "approximately 10 explosive devices and several firebombs were used to target the security fence and (Israeli) troops". It said shots were also fired at soldiers.

The embassy inauguration followed Trump's December 6 recognition of Jerusalem as Israel's capital.

Israel occupied the West Bank and east Jerusalem in 1967 and later annexed east Jerusalem in a move never recognised by the international community.

Jerusalem's status is perhaps the thorniest issue in the Israeli-Palestinian conflict.

Israel considers the entire city its capital, while the Palestinians see east Jerusalem as the capital of their future state.

International consensus has been that the city's status must be negotiated between the two sides, but Trump broke with that to global outrage.

He has argued that it helps make peace possible by taking Jerusalem "off the table", but many have noted he has not announced any concessions in return from Israel.

Beyond the disputed nature of Jerusalem, the date of the embassy move was also key. May 14 marks the 70th anniversary of the founding of Israel.