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, reported a continuous flow of Palestinians moving south, yet hundreds of thousands remain in the city. The World Health Organization (WHO) has expressed concerns that healthcare facilities are nearing collapse due to their inability to receive essential supplies.

The Israeli military stated its operations aim to dismantle what it describes as terror infrastructure in Gaza City, which is characterized as a stronghold for Hamas, and to rescue hostages still in captivity.

However, the offensive has drawn international condemnation, with rights groups highlighting the precarious situation for civilians in a city that previously housed one million residents and is now suffering from famine.

UN and humanitarian agencies estimate that at least 200,000 people have crossed from northern to southern Gaza since mid-August in anticipation of the military offensive, but many remain unable to escape.

Cherevko described witnessing multiple Israeli strikes while on her way to Gaza City, emphasizing how crowded the city remains with civilians amid the ongoing conflict.

In the latest assaults, many families seeking shelter are forced to stay outdoors without adequate provisions. The WHO has noted that hospitals remain overcapacity, accommodating 180 to 300% more patients than their designed capacity.

The humanitarian implications are severe, as indicated by the UN Population Fund, which reported women giving birth in the streets due to lack of accessible healthcare facilities.

The Israeli military's operations began following a Hamas-led attack on southern Israel which resulted in over a thousand deaths, leading to strategic military responses targeting Gaza, complicating the already dire humanitarian landscape.