The Gaza Strip could be on the brink of a new humanitarian crisis if supplies are not allowed in, authorities say, as Israel responds to the Hamas attacks.
On Monday, Israel declared a “complete siege” on the territory, saying electricity, food, fuel and water would be cut off.
According to residents, aid has not reached the enclave since Saturday.
BBC footage shows deserted streets covered with rubble from collapsed buildings following Israeli airstrikes.
Nearly 700 people have died in these attacks and thousands more are reported to have been injured.
The area is home to about 2.3 million people in total – 80% of whom rely on humanitarian aid mainly due to the ongoing hostilities with Israel.
It is ruled by Hamas militants but Israel controls the airspace and its shoreline. It also restricts who and what goods can cross its borders.
Neighbouring Egypt strictly controls what or who can pass through its border with Gaza too.
Since the attacks began on Saturday morning, Israel has stopped all supplies entering Gaza, including food and medicine.
Stéphane Dujarric, spokesman for the UN secretary-general, said more than a dozen healthcare workers had been killed or injured and at least seven medical centres had been damaged.
Meanwhile, many people are currently without electricity and internet, and could soon be out of essential food and water supplies.
“Damage to water, sanitation and hygiene facilities has undermined services to more than 400,000 people,” said Mr Dujarric.
“The Gaza Power Plant is now the only source of electricity and could run out of fuel within days.”
He added that the World Food Programme was already distributing food for up to 100,000 internally displaced Palestinians and that these efforts would increase eight-fold in the coming days.
Even before the latest restrictions, residents of Gaza already faced widespread food insecurity, restrictions on movement and water shortages.
Juliet Touma, a spokeswoman for the United Nations’ Palestinian refugee agency (UNRWA), told the BBC people in Gaza were “terrified” by the current situation and worried for their safety – as well as that of their children and families.