Israel says it has begun sending troops into Gaza as part of a larger ground operation aimed at pushing Hamas to demilitarize and release the remaining hostages it holds.

Israel launched an extensive ground operation in Gaza Sunday in addition to an intense air campaign that health officials in the territory say killed over 100 people overnight and shuttered the last functioning hospital in the enclave’s north.

Israel had blocked the entry of medical, food and fuel supplies into Gaza since the start of March to try to pressure Hamas into freeing its hostages.