(NewsNation) — Israel’s retaliation against Hamas has escalated greatly since the militant group that controls Gaza attacked the country Saturday.

The Gaza Health Ministry says 1,900 people have been killed in the territory since war broke out Saturday, more than half of the deaths being of women and children, while the Hamas assault killed more than 1,300 Israelis, most of whom were civilians. According to the Israeli government, roughly 1,500 Hamas militants were killed during the fighting.

Palestinians fled from northern Gaza Friday after Israel’s military told them to evacuate ahead of an expected ground invasion. It’s a move the United Nations warned would be calamitous for the 1.1 million people affected, especially as Israel stopped the entry of food, water, fuel and medicine into Gaza. The organization urged Israel to reverse the unprecedented directive.

“Forcible population transfers constitute a crime against humanity, and collective punishment is prohibited under international humanitarian law,” Paula Gaviria Betancur, special rapporteur on the human rights of internally displaced persons, said in a statement. “We are horrified at the prospect of an additional 1 million Palestinians joining the over 423,000 people already forcibly driven from their homes by the violence over the past week.”

The International Committee of the Red Cross said the order to leave, along with Israel’s military siege of Gaza, is not “compatible with international humanitarian law.”

Meanwhile, Hamas called the evacuation “psychological warfare” to break Palestinian solidarity and told people to stay.

However, Israel Defense Forces spokesperson Jonathan Conricus, in an interview with NewsNation’s Cornell McShane, said the point of Israel telling those in Gaza to evacuate is to get as many civilians as possible out of the area because “of a concern for their safety.”

Israel wants to be able to operate while minimizing the effect on civilians, Conricus said.

Evacuating “won’t be beautiful, and it won’t be comfortable,” Conricus said, pointing out Israelis also had to leave the “torched remains of their villages and kibbutzim.”

“That wasn’t beautiful either. We evacuated our civilians from the border area because we don’t want them to be in an active combat zone, and out of a concern for civilians in Gaza, we are asking them to do the same,” Conricus said. “Will it be an orderly and well-executed peaceful movement of people? Most likely not — we are at war. At war, unfortunately, horrible things happen. What we are trying to do is to minimize the horror to minimize the effect on civilian casualties.”

Conricus said the IDF’s plan is for a complete military dismantling of Hamas.

The Associated Press contributed to this report.