Scotland's First Minister Humza Yousaf posted a video online Friday showing his British mother-in-law in Gaza tearfully deploring Israel's order to evacuate more than one million people from the north of the Palestinian enclave.

"This will be my last video", Elizabeth al-Nakla, a UK citizen who was visiting relatives there when the latest hostilities erupted, said in the recording shared by the Scottish leader on X, formerly Twitter.

Nakla, a former nurse, said people from Gaza City in the northern Gaza Strip were moving southward after Israel gave Palestinians 24 hours to leave the besieged enclave's largest city.

It comes ahead of an expected ground offensive in retaliation against Hamas for the deadliest attack in Israeli history last weekend.

"One million people — no food, no water, and still they are bombing them as they leave. Where are we going to put them?" Nakla said.

"But my (first) thought is, all these people in the hospital cannot be evacuated.

"Where's humanity? Where's people's hearts in the world to let this happen in this day and age," she said crying. "May God help us. Goodbye."

The United Nations said it had been informed of Israel's evacuation order shortly before midnight Thursday, nearly a week after hundreds of Hamas gunmen broke through the militarised barrier around the overcrowded Gaza Strip by land, sea and air. Their assault killed more than 1,300 people in Israel.

However Israel's military did not confirm the UN report that it had set a 24-hour deadline, admitting Friday it would take time for Palestinians to follow its orders to evacuate northern Gaza.

'Angry' 

The UN said the mass relocation, affecting 1.1 million, or about half the entire population of the Gaza Strip, to the territory's south was "impossible" and urgently appealed for the order to be rescinded.

During an emotional interview with Sky News, Scotland's Yousaf cried when discussing how "powerless and helpless" he felt about the situation.

He also accused the UK government of failing to help, saying he wrote to Foreign Secretary James Cleverly and was "angry" and "disappointed" to receive no reply.

"He was in Israel and could have picked up the phone to me and made assurances about getting two UK citizens out," said Yousaf, referring to Cleverly's midweek visit to Israel.

In a separate interview with the BBC, the Scottish leader said that Israel was "going too far" with its response to the Hamas attack.

"Collective punishment cannot be justified," said Yousaf, adding that innocent people were "paying an extraordinary price for those atrocious attacks that they have nothing to do with".

Israel has declared war on Hamas and fired thousands of munitions at targets in Gaza, flattening entire neighbourhoods and sending residents fleeing for safety, since Saturday.

UN humanitarian agency OCHA, citing Palestinian authorities, said more than 2,500 homes have been destroyed or made uninhabitable by the bombing.

Israel's Defence Minister Yoav Gallant on Monday ordered a "complete siege" of Gaza, meaning "no electricity, no food, no water, no gas".

The United Nations criticised that as a possible violation of international law.