Israel warns of new phase in war against Hamas, as Gaza civilians flee and Israeli troops gather near border

A new phase in Israel's deadly war against Hamas is coming, Israeli forces said on Saturday, warning that the past week of crippling airstrikes in Gaza could soon be followed by "significant ground operations."

Israeli troops and military equipment have massed at the border with Gaza as Israel prepares to ramp up its response to a deadly October 7 attack by the Islamist militant group Hamas, which controls the enclave. Warplanes continued to blast Gaza over the weekend, as civilians fled southward, following evacuation instructions by the Israel Defense Forces (IDF).

Several United Nations agencies have warned that mass evacuation under such siege conditions will lead to disaster, and that the most vulnerable Gazans, including the elderly and pregnant, may not be able to relocate at all. For days, Israel has cut off the Gaza population's access to electricity, food and water.

"The order to evacuate 1.1 million people from northern Gaza defies the rules of war and basic humanity," wrote Martin Griffiths, head of the United Nations Office for the Coordination of Humanitarian Affairs, in a statement late Friday. "Roads and homes have been reduced to rubble. There is nowhere safe to go."

Following an apparent explosion on Friday, extensive destruction could be seen on Salah Al-Deen street - a main route for evacuation - in videos authenticated by CNN. A number of bodies, including those of children, can be seen on on a flat-bed trailer that appears to have been used to carry people away from Gaza City.

It's unclear what caused the blast. CNN has reached out to the IDF for comment on any airstrikes in the same location.

Israeli military airstrikes have killed 70 evacuees and injured 200 more since the first evacuation order was issued Friday, Hamas' media office told CNN. According to the Palestinian Ministry of Interior and National Security, Palestinian medical services and civil defense crews were targeted by an Israeli strike at the site of a rescue operation in northern Gaza on Saturday.