The Israeli military said it was gradually expanding its ground operations inside Gaza, while stopping short of calling it an all–out invasion. Casualties on both sides are expected to rise sharply as Israeli forces and Palestinian militants battle in dense residential areas.

“We are proceeding with the stages of the war according to an organized plan,” Hagari, the military spokesman, said. The comments hinted at a strategy of staged escalation, instead of a massive and overwhelming offensive.

Despite the Israeli offensive, Palestinian militants have continued firing rockets into Israel, with the constant sirens in southern Israel a reminder of the threat.

The Palestinian death toll in Gaza rose Saturday to just over 7,700 people since the war began, with 377 deaths reported since late Friday, according to the Gaza Health Ministry. Most of those killed have been women and minors, the ministry said.

An estimated 1,700 people remain trapped beneath the rubble, according to the Health Ministry, which has said it bases its estimates on distress calls it received.

Israel says its strikes target Hamas fighters and infrastructure and that the militants operate among civilians, putting them in danger.

More than 1.4 million people across Gaza have fled their homes, nearly half crowding into U.N. schools and shelters, following repeated warnings by the Israeli military that they would be in danger if they remained in northern Gaza. No one has been allowed out of the sealed–off territory, and Israel has allowed only a trickle of food and medical aid to enter from Egypt.

Gaza’s sole power plant shut down shortly after the start of the war, and Israel has allowed no fuel to enter, saying Hamas would use it for military purposes.

Hospitals are struggling to keep emergency generators running to operate incubators and other life–saving equipment, and the U.N. agency for Palestinian refugees is also trying to keep water pumps and bakeries running to meet essential needs.

The conflict has threatened to ignite a wider war across the region, with Lebanon’s militant Hezbollah trading fire with Israel along the border. In recent days, both Israel and the U.S. have struck targets in Syria that they say are linked to Iran, which backs Hamas, Hezbollah and other armed groups in the Middle East. The U.S. said it was responding to attacks on American forces in Syria and Iraq.

Israeli forces have also traded fire with Palestinian militants in the occupied West Bank, where over 100 Palestinians have been killed since the start of the war, mostly during military raids and violent protests. The Palestinian Health Ministry said three Palestinians were killed early Sunday as Israeli forces carried out raids across the occupied territory, where Israel says it has detained hundreds of Hamas members.