Hamas warned Sunday that no hostages would leave Gaza alive unless its demands for prisoner releases are met, while the World Health Organization said the territory’s health system was collapsing after more than two months of war. Hamas triggered the conflict with the deadliest-ever attack on Israel on October 7 in which it killed some 1,200 people, according to Israeli figures, and dragged around 240 hostages back to Gaza. Israel has responded with a relentless military offensive that has reduced much of Gaza to rubble and killed at least 17,997 people, mostly women and children, according to the Hamas-run health...