The ministry said four patients at Nasser Medical Complex died from lack of oxygen when generators cut out. The claims could not be independently verified.
The Friends Committee, a Quaker lobbying group, has been pushing in Washington for a cease-fire, going up against more powerful and better-funded groups backing Israel.
Israel says Hamas routinely operates within — and beneath — places like Nasser hospital in Khan Younis, using them as shields, and has held Israeli hostages there. The group denies the charges.
To dull his heartache, Mustafa Abutaha told stories of people sheltering with him at Nasser hospital; he later fled before the Israeli military closed in. Israeli forces began raiding the medical facility on Thursday.