The situation in Gaza City is nothing short of cataclysmic, a UN official has told the BBC, as Israeli tanks and troops continue to advance on the third day of a ground offensive.
Olga Cherevko, a spokeswoman for the UN's humanitarian office, said she had seen a constant stream of Palestinians heading south during a recent visit to the city, but that hundreds of thousands remained.
The World Health Organization (WHO) warned that overwhelmed hospitals were on the brink of collapse because it was being prevented from delivering lifesaving supplies.
The Israeli military said its forces were dismantling terror infrastructure and eliminating terrorists in Gaza City.
It has said its objectives are to free the hostages still held by Hamas and defeat up to 3,000 fighters in what it has described as the group's main stronghold.
However, the offensive on Gaza's biggest urban area, where one million people were living and a famine was confirmed last month, has drawn widespread international condemnation.
The UN and its humanitarian partners have recorded at least 200,000 people crossing from northern to southern Gaza since mid-August, when Israel announced its intention to conquer Gaza City. Around 55,000 have made the journey since Sunday.
Cherevko, who works for the UN humanitarian office in the central city of Deir al-Balah, told the BBC she travelled to Gaza City two days ago - a 29km (18 mile) round-trip that took 14 hours.
The things there, and the scenes on the way to Gaza City, are nothing short of cataclysmic, she recalled.
A constant stream of people [are] crossing from the north to the south, many on foot. Inside Gaza City, it's very crowded still because there are hundreds of thousands of civilians still remaining there.
She said she also witnessed multiple Israeli strikes very close to the UN convoy while in Gaza City, adding: It was really just a constant hit after hit while we were there.
On Thursday morning, witnesses told Reuters news agency they had seen Israeli tanks in the northern Sheikh Radwan neighbourhood and the southern neighbourhood of Tal al-Hawa, which have come under heavy bombardment in recent days.
Local hospitals said at least 14 people had been killed by Israeli fire across the Gaza Strip on Thursday, including nine in Gaza City.
The WHO's chief, Dr. Tedros Adhanom Ghebreyesus, stated the offensive is forcing traumatized families into an ever-shrinking area unfit for human dignity. Reports indicated that many injuries are being neglected due to the overwhelming burden on healthcare systems.
Al-Rantisi children's hospital has suffered severe damage due to bombings, exacerbating the challenges for the medical community in providing care. Furthermore, the UN Population Fund highlighted that women are giving birth without access to clean medical facilities.
