Seventeen British nationals, including children, are feared dead or missing in Israel after an attack by Hamas, Sky News understands.

Three Britons are already confirmed to have died in the weekend’s attack, which has so far claimed at least 2,100 lives in total.

Among those known to have died is 20-year-old Nathanel Young, who was serving in the Israeli army when he was killed during Hamas’s charge.

Bernard Cowan, who grew up around Glasgow, also died while Jack Marlowe, 26, who went to the same London school as Mr Young, is believed to be missing.

Photographer Dan Darlington was confirmed to have died after a post from his sister, Shelley, on social media said he was “murdered” at Nir Oz, in southern Israel.

To outline the UK’s support for Israel, foreign secretary James Cleverly arrived in the country, where he will also meet survivors on Wednesday afternoon.

Israel-Gaza latest: Israel vows to ‘wipe out’ Hamas after boys ‘beheaded’

At least 1,200 Israelis are dead and more than 2,700 have been wounded, according to the latest figures supplied by the IDF (Israel Defence Forces).

The latest information from Gaza’s Health Ministry said that at least 1,055 Palestinians have been killed and 5,184 wounded in Israeli strikes, with authorities claiming two-thirds of those injured are women and children.

Israeli warplanes hammered the Gaza Strip through the night into Wednesday morning, reducing buildings to rubble and reportedly striking over 450 targets.

Its air force has also targeted southern Lebanon, with Israel claiming to have struck a Hezbollah lookout position in retaliation for cross-border fire.

Meanwhile, Israel has stopped entry of food, fuel and medicines into Gaza, and the sole remaining access from Egypt shut down on Tuesday after airstrikes hit near the border crossing, with the violence expected to escalate further.

Israel vows to ‘wipe out’ Hamas

To many of the 2.3 million residents in the Gaza Strip, the mobilisation and intense bombardment raise fears of a ground invasion that may surpass Israel’s incursions in 2008 and 2014.

One Israeli security source said a ground offensive now looked inevitable, while Sky News military analyst Michael Clarke believes Israel would prefer a multi-pronged attack into Gaza, probably from the land and sea simultaneously.

It comes as Israel vowed to “wipe out” Hamas after claiming children were burnt alive, beheaded and shot in the head, a government minister from the country told Sky News.

Israel’s economics minister Nir Barkat said its military operation would continue until there was a “clear white flag” and there was a “more moderate” replacement for the militant group that rules in the Gaza Strip.

“Just now, we have heard of 40 young boys, some of them were burnt alive, some were beheaded, some were shot in the head,” the minister told Sky’s Mark Austin – although the IDF has not confirmed this.

Sky News’ chief correspondent, Stuart Ramsey, spoke to two IDF majors – neither or whom mentioned children or babies beheaded, though it’s clear there was a “horrific attack” in Kfar Aza, one of the first places attacked by Hamas.

Mr Barkat added: “The whole country is united to take Hamas out of this world, to take them out. All the militants, all the infrastructure, the people supporting Hamas. We will wipe them out.

“We’re coming in to kill the militants, and any civilians [should] move aside. If you do not move aside and you’re giving cover to the Hamas militants, you’re risking your life.

“We do not want to hurt innocent people.”

Many Palestinians in the Gaza Strip have no way of escaping, with the Egyptian border still closed in the south.

Gaza ‘running out of power’

A ground offensive carries risks for Israel, notably to the hostages held in the narrow and densely populated Gaza Strip, with Hamas threatening to execute a captive for each home hit without warning.

As violence escalates, residents in Gaza are facing an imminent loss of electricity as fuel supplies run dangerously low, while hospitals struggle with dwindling medical supplies.

Jalal Ismail, from Gaza’s energy authority, had said power will run out in the city by midday, which has now passed.

“The power plant will stop working completely today at 2pm (12pm UK time), due to the exhaustion of the amount of fuel needed to operate it,” he said.

Israel withdrew troops from Gaza in 2005 after 38 years of occupation, with Hamas seizing power in 2007.

Since then, Israel has kept it under blockade, creating conditions Palestinians say are intolerable.