More than one million people have fled their homes in Gaza in scenes of chaos and despair as Israel bombarded the Hamas-ruled territory and continued massing troops Monday in preparation for a full-blown ground invasion.

Israel declared war on the Islamist group a day after waves of its fighters broke through the heavily fortified border on October 7, shooting, stabbing and burning to death more than 1,400 people, most of them civilians.

After it suffered the deadliest attack in its history, Israel unleashed a relentless bombing campaign of the Gaza Strip that has flattened neighbourhoods and killed at least 2,670 people, mainly civilians.

Following an Israeli order to move to the south of the Gaza Strip, people have fled their homes in the north of the enclave to seek shelter wherever they can, including on the streets and in UN-run schools.

Palestinians carrying whatever belongings they can, in bags and suitcases, or packed onto three-wheeled motorbikes, battered cars, vans and even donkey carts have become a common sight.

“No electricity, no water, no internet. I feel like I’m losing my humanity,” said Mona Abdel Hamid, 55, who fled Gaza City to Rafah in the south of the enclave, and is having to stay with strangers.

US President Joe Biden said in an interview with the CBS news programme 60 Minutes that while invading and “taking out the extremists” was needed, any move by Israel to occupy Gaza would be a “big mistake”.

– ‘Verge of abyss’ –

A bereaved and infuriated Israel has massed forces outside the long-blockaded enclave of 2.4 million in preparation for what the army has said would be a land, air and sea attack involving a “significant ground operation”.

“We are at the beginning of intense or enhanced military operations in Gaza City,” spokesman for the Israeli Defense Forces (IDF) Jonathan Conricus said.

“It would be unsafe for civilians to stay there,” he added.

Hamas backer Iran and Lebanon’s Hezbollah, which is also supported by Tehran, have warned that an invasion of Gaza would be met with a response.

“No one can guarantee the control of the situation and the non-expansion of the conflicts” if Israel sends its soldiers into Gaza, said Iran’s Foreign Minister Hossein Amir-Abdollahian.

Fire along the Israeli-Lebanese border has intensified in the last week, prompting Israel to shutter the area to civilians.

On Sunday, a rocket hit the UN peacekeeping base in southern Lebanon, while Hezbollah attacks killed one person in Israel, the Israeli military said.

More than 10 people have been killed in Lebanon and at least two in Israel in the past week.

Among those killed in Lebanon was a Reuters journalist, Issam Abdallah.

US Secretary of State Antony Blinken was due back in Israel on Monday after a crisis tour of Middle Eastern countries in a frantic attempt to avert a wider crisis in the volatile region.

But as Israel seeks to avenge the brutal attack, that also saw Hamas militants take scores of hostages including young children, the Arab League and African Union have warned an invasion could lead to “a genocide of unprecedented proportions”.

UN chief Antonio Guterres has warned that the entire region was “on the verge of the abyss”.

– Escalation risk –

Israel’s Defence Minister Yoav Gallant said his country had “no interest in a war in the north, we don’t want to escalate the situation”.

The United States, which has given unequivocal backing to Israel, has sent two aircraft carriers to the eastern Mediterranean as a deterrent.

The White House has voiced fears at the prospect of Iran becoming “directly engaged”, after Tehran praised the Hamas attack but insisted it was not involved.

But asked in the 60 Minutes interview whether US troops might join the war, Biden said “I don’t think that’s necessary”.

“Israel has one of the finest fighting forces in the country. I guarantee we’re gonna provide them everything they need,” he said.

The United States has also appealed to China to use its influence in the region to ease tensions.

On Sunday Foreign Minister Wang Yi said Israel’s response had “gone beyond the scope of self-defence”, and demanded that it “cease its collective punishment of the people of Gaza”.

– Aid agencies’ alarm –

Massing thousands of troops and heavy weaponry in the desert south of the country, the Israeli military has said it is awaiting the “political” green light to go into northern Gaza.

The army has told 1.1 million Palestinians in the north of the Gaza Strip to head to the south of the enclave.

But Israeli air strikes were continuing in the south, including in Khan Yunis and Rafah, where one resident said a doctor’s house was targeted.

“All the family was wiped out,” said Khamis Abu Hilal.

The UN said Monday that 47 entire families, amounting to around 500 people, have been wiped out in Israel’s bombing campaign.

Foreign governments and aid agencies, including the UN and Red Cross, have repeatedly criticised Israel’s evacuation order.

The UN agency supporting Palestinian refugees said Sunday that some one million Palestinians had already been displaced in the first week of the conflict — but the number was likely to be higher.

Lynn Hastings, the UN humanitarian coordinator for the Palestinian territories, decried that Israel was connecting humanitarian aid into Gaza with the release of scores of hostages kidnapped during the Hamas attack.

“Neither should be conditional,” she insisted in a video posted by the UN.

“They have said they want to destroy Hamas, but their current trajectory is going to destroy Gaza.”

– Evacuations –

In Gaza, hospitals are becoming overwhelmed with increasing numbers of dead and injured, with officials saying Sunday that some 9,600 people have been wounded.

Israeli energy minister Israel Katz on Sunday said water supplies to southern Gaza had been switched back on.

But power outages threaten to cripple life-support systems, from sea water desalination plants to food refrigeration and hospital incubators.

Even everyday functions — from going to the toilet, showering and washing clothes — are almost impossible, locals said.

Gazans are effectively trapped, with Israeli-controlled crossings closed and Egypt also having shut the Rafah border in the south.

Blinken said he was confident the crossing “will be open” for aid into the strip, amid reports that Egypt was blocking the passage of Gazans with foreign passports until relief supplies are allowed in.

He categorically rejected the idea floated of expelling Palestinians from the Gaza Strip.

The mood in Israel has swung between collective grief, fury and a strong desire to punish Hamas, which Netanyahu has likened to the Islamic State group. It is proscribed as a terrorist group by several Western governments, including the United States.

There are deep fears about the safety of 155 hostages that Hamas took into the Gaza Strip during its attack.

“We must bring them back home alive,” said a tearful Yrat Zailer, the aunt of children aged nine months and four years whom Hamas abducted along with their mother.