Nothing new in Gaza: already in 2014, Shifa Hospital had become the De Facto Hamas HQ

https://www.algemeiner.com/2014/07/21/washington-post-shifa-hospital-in-gaza-city-has-become-a-de-facto-headquarters-for-hamas-leaders-who-can-be-seen-in-hallways-and-offices/

Contrary to international rules of warfare, Hamas has commandeered a large hospital in Gaza City as
its "de facto headquarters," the Washington Post reported.

[...]

"During the lull, a group of men at a mosque in northern Gaza said they had returned to clean up
the green glass from windows shattered in the previous day's bombardment. But they could be seen
moving small rockets into the mosque."

According to international rules of military engagement,  civilian public and religious buildings
cannot to be used to shield weapons, but that has been a long-held Hamas tactic in Gaza.

On Thursday, UNRWA, the United Nations Relief and Works Agency for Palestine Refugees in the Near
East, said it discovered 20 rockets hidden in a vacant school it operated in Gaza.