The GMO says the proportion of women and children killed in the conflict is around 70%.

The UN's latest report, citing health ministry data, says out of 24,686 fully identified fatalities, 52% were women and children, 40% were men, and 8% were "elderly", without specifying whether they were male or female.

It isn't clear what age the report considers to be "elderly" and how it categorises children.

We have done our own analysis of detailed data released by the health ministry, and also found that 52% of the fatalities were listed as women and children (anyone under 18). In addition, 43% were men and another 5% were "unknown" (missing information such as an age or gender).

For the GMO's figure to be compatible with the health ministry's data, almost all of the 10,000 deaths not fully identified by the ministry would have to have been women and children.

"It's not logically impossible... but it really strains credibility," says Prof Michael Spagat, who specialises in examining death tolls in conflicts around the world.

We asked the GMO why the proportion of women and children they have recorded as killed is so much higher than in the health ministry's data, but they did not provide a direct response to the discrepancy.

We also approached the health ministry for comment.

Prof Spagat also told the BBC that the death toll in Gaza was "staggeringly high" given the war has only been going on for six months, noting that the verified hospital deaths still represent about 1% of Gaza's pre-war population of 2.4 million.

Asked by BBC Verify why it made the change, the UN said it used the GMO data for women and children killed because the health ministry had not been publishing these figures.

"Once the ministry of health in Gaza published breakdowns that were more comprehensive, backed up by a list of names, the UN reports reflected that data instead," a UN spokesman said.

He added that in both cases, the figures were attributed to their source and a "clear note" was added making clear the UN's "inability to presently provide an independent confirmation of the data".

The UN has previously said that it has a "long-standing co-operation" with the Gaza health ministry, and that its previous reporting has been considered credible and "well developed".

Data analysis by Rob England and Daniel Wainwright