The chief surgeon for the International Committee of the Red Cross has given a harrowing account of an amputation his team performed at a hospital in southern Gaza in a video diary shared with Sky News.
Dr Tom Potokar said his team had to amputate the hand of a six-year-old child with "very deep burn injuries".
He said the boy's hand had been "charred" and was the cause of ongoing infection which was making him very unwell.
The child remains in a critical condition.
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Dr Potokar sent the eyewitness account from the European Gaza Hospital in southern Gaza.
He described "another very busy day" in theatre where his team were dealing with "very limited resources, very limited monitoring and really far from ideal circumstances anesthetising patients".
They are, nevertheless, able to get patients in a position where they can operate on them, thanks to the "amazing" work of his anaesthetist, he said.
Israel has been urging civilians in northern Gaza to travel to the south as it continues to push forward with its ground operations following the 7 October attacks.
However, bombardments have continued in the south.
Dr Potokar said patients are still arriving at the hospital where colleagues are dealing with "many burns", complicated blast injuries with extensive tissue loss and bone injury.
A nursing staff shortage was presenting a major challenge due to the large number of dressing changes they are having to contend with, he said.
They are also "inundated with internally displaced people", he added.
Meanwhile, Dr Potokar said bombardment continues every night, including "one very close at 1.30am this morning which whistled over the top of the building".
To the north, Israeli strikes have been pounding Gaza City as ground forces battle Hamas fighters near its largest hospital.
Health officials said medics, patients and displaced people were trapped in the al Shifa Hospital with no electricity and dwindling supplies.
Israeli Prime Minister Benjamin Netanyahu has rejected growing international calls for a ceasefire, saying Israel's battle to crush Hamas militants will continue with "full force".