Expectations of an Israeli ground assault into Gaza City were growing early Saturday, as the end of a 24-hour evacuation warning by the Israeli military for Gazans to evacuate the northern part of the enclave approached. The potential Israeli operation heightens the risk to the safety of the hundreds of thousands of civilians in the Gaza Strip, possibly including hostages taken by Hamas in its unprecedented cross-border attack. Israel has accused the militant group of using civilians as “human shields,” and that Gazan civilians are not Israel’s enemies. Israeli Prime Minister Benjamin Netanyahu said he had spoken to some of the relatives of the hostages.