Sixty-eight Palestinians - including 10 children - have been killed or their bodies recovered in the last 24 hours, the United Nations said.
At least 857 Palestinians have now been killed in the conflict, with around 649 of the fatalities reported to be civilians.
The UN said shelters were becoming increasingly overcrowded with many classrooms holding 80 people at one one time.
Health professions and facilities are becoming overstretched, the organisation claimed, reporting an increase in the number of miscarriages and premature births,
The updated figures come ahead of an agreed 12-hour humanitarian ceasefire between Israel and Hamas.