More than one million residents of Gaza City Friday were warned by the Israeli military to evacuate and move to the south in the next 24 hours, as it deployed its tanks near the Gaza Strip amid fears of a major ground offensive.

As the Israeli warplanes continued attacking Gaza, its Defence Minister Yoav Gallant said: “Now is a time for war.”

The military has warned about “significantly” operating in Gaza City in the coming days, insisting that the residents will only be able to return when a relevant announcement is made.

Earlier, the United Nations had told Reuters about the Israeli military’s warning, which, as feared by Palestinians, could result in Israel’s planned ground offensive.

No comments were immediately issued by the Israeli military regarding the warning. However, it had amassed tanks near the Gaza border and struck the Palestinian enclave with air strikes in the wake of Hamas’s fight to free Gaza from Israel’s decades-long occupation.

“The United Nations considers it impossible for such a movement to take place without devastating humanitarian consequences,” Stephane Dujarric, a UN spokesperson, said in a statement.

She added that the UN strongly appeals for any such order, if confirmed, to be rescinded avoiding what could transform what is already a tragedy into a calamitous situation.

Dujarric said the order by the Israeli military also applied to all UN staff and those sheltered in UN facilities, including schools, health centres and clinics.

But appearing to confirm a warning took place, Israel’s ambassador to the UN, Gilad Erdan, said: “The UN’s response to Israel’s early warning to the residents of Gaza is shameful.”

Erdan said the UN should focus on condemning Hamas and supporting Israel’s right to self-defence.

Salama Marouf, head of the Hamas government media office, said the relocation warning was an attempt by Israel “to broadcast and pass on fake propaganda, aiming to sow confusion among citizens and harm our internal cohesion.”

He added: “We urge our citizens not to engage in these attempts”.

More From Fact-File: UN report unveils Gaza displacement crisis amid Israel-Hamas conflict

The International Committee of the Red Cross (ICRC) said fuel powering emergency generators at hospitals in Gaza could run out within hours and the United Nations World Food Programme (WFP) warned food and fresh water were running dangerously low.

“The human misery caused by this escalation is abhorrent, and I implore the sides to reduce the suffering of civilians,” ICRC regional director Fabrizio Carboni said.

So far, Israel’s bombings have martyred over 1,500 Palestinians hundreds of which include children, Gaza authorities said. The Israeli forces have also killed four medics, which the Palestinian Red Crescent claimed were murdered deliberately.

Israel has so far put Gaza, home to 2.3 million people, under siege and launched a bombing campaign that destroyed whole neighbourhoods.