The UN Office for the Coordination of Humanitarian Affairs (OCHA) is estimating that at least 100,000 people have moved into Rafah, the most southerly city in Gaza, in recent days as fighting intensifies in Khan Younis and elsewhere.
Israel has told people to leave parts of Khan Younis, which it sees as a stronghold of Hamas.
The OCHA says the influx of people has made overcrowding worse and put pressure on limited resources.
There is also concern about a rise in the spread of diseases in Gaza, with some families having to move multiple times.
BBC
