The source is GMO, the Government Media Office - which means Hamas.
The UN officially repeated that figure, along with other Hamas statistics, at a press conference in Geneva last week:
“Over 33,000 Palestinians, mostly women and children, are dead, 75,000 or more are injured, and at least 7,000 are presumed dead under the rubble. .... Huge swathes of Gaza have been bombed into oblivion. The Gaza Strip has changed forever,” spokesperson Jeremy Laurence told the biweekly press briefing in Geneva.
That same 7,000 number has been quoted for months. As the New York Times wrote last month, "The most recent health ministry estimate for the number of people missing in Gaza is about 7,000. But that figure has not been updated since November. Gaza and aid officials say thousands more have most likely been added to that toll in the weeks and months since then."
Really? More bodies have been buried than found since November? The entire northern half of Gaza has thousands of bodies that have been under rubble for months?
One would have thought that during the humanitarian pause at the end of November there would have been lots of bodies found, reducing the total number. Similarly, since the number of airstrikes has gone down significantly in the past couple of months, one would think that the 7,000 number would be going down, not up.
It doesn't take much thought to realize that the 7,000 number was made up. There is no central Gaza office that tracks missing people or people presumably buried under rubble, so how can such an estimate be made or maintained?
Hamas published the number (as OCHA admits) and no one is going to disagree with them. And the UN and New York Times and NGOs all quote the figure as if there is a legitimate government organization in Gaza that is keeping track.
It is just another example where, at the same time every Israeli statement is treated as a potential lie or at the very least an unverified claim, every Hamas statement is assumed to be true.
And no one is held accountable for believing and repeating Hamas lies.
