Palestinians who fled an ongoing Israeli raid of Gaza's main hospital have told The Associated Press of mass arrests and forced marches past dead bodies. Israel's military says it has killed more than 170 militants and detained about 480 suspects in the raid on Shifa Hospital that began Monday. The fighting highlights the resilience of Palestinian armed groups in a heavily destroyed part of Gaza targeted in the war's earliest weeks. The United Nations says that Israel is now blocking its main agency helping Palestinians from sending food aid to the enclave’s devastated north. Experts have warned of imminent famine there.