Israel’s military is advancing into southern Gaza in a push that ushers in a new phase of its war against Hamas — and an increasingly perilous situation for Palestinian civilians who have few safe places left to flee. Israel says Hamas leaders who planned the Oct. 7 attack are sheltering in the south. Satellite imagery showed dozens of armored vehicles about 1½ miles north of Khan Younis, the largest city in the south. “For people ordered to evacuate, there is nowhere safe to go and very little to survive on,” a spokesman for U.N. Secretary General António Guterres said. A territory-wide communications blackout also hampered the humanitarian response overnight.