Smoke rises following an Israeli military strike in Gaza City, as seen from the central Gaza Strip, on Wednesday. Jehad Alshrafi - the associated press

By SAMUEL GRANADOS AND AARON BOXERMAN | THE NEW YORK TIMES

The Israeli military has razed block after block of Gaza City as part of a new ground offensive in what was once the territory's largest urban center.

Israel's war against Hamas, which began two years ago, has leveled wide swaths of the Gaza Strip, including the city of Rafah in the south and the town of Beit Hanoun in the north. But the military did not carry out such widespread demolitions in previous Gaza City operations.

This time is different.

Although much of the city is still standing, satellite images show Israeli forces are destroying whole areas as they sweep into Gaza City, including the Zeitoun neighborhood and an area near Sheikh Radwan, where the military has demolished dozens of structures this month.

Previously, Israeli troops advanced through Gaza City and then withdrew - only to return later to fight what they said was a renewed Hamas insurgency. Prime Minister Benjamin Netanyahu of Israel said this time was different because the military would hold areas it seized.

"We capture territory and we hold it. We clean it out and we move forward," he said in an interview last month with Channel 14, a right-wing Israeli television station.

Netanyahu says the offensive aims to decisively rout Hamas from one of its last strongholds in the Gaza Strip. But even many Israelis are skeptical that this strategy will succeed now, as Hamas has proved resilient in the face of nearly two years of devastating war. The Israeli ground offensive has forced hundreds of thousands of Palestinians to flee their homes in Gaza City, crowding into swelling tent camps in central and southern Gaza.

This has exacerbated what was already a humanitarian catastrophe in Gaza, with rampant hunger, mass displacement and a collapse of health care, schools and infrastructure. Many war-weary Gaza City residents say they simply cannot or will not be displaced again, and many have no homes to return to.

While closing in on Gaza City, Israel has used existing buildings as bases, only to later destroy them with explosives before moving onward, according to satellite images and videos verified by The New York Times.

One video shows the military destroying Al-Furqan, a school in the city it had earlier used as a military position.

In addition to carrying out demolitions, the Israeli military has also kept up airstrikes across Gaza City, striking hundreds of targets since mid-September.

In a satellite image from Sept. 18, the latest high-resolution image available from Planet Labs, a commercial satellite company, fewer tents could be seen compared with a time before Israel announced the launch of its Gaza City ground offensive two days earlier. Still, hundreds of tents were visible, many within around a mile oflsraeli military vehicles.

Israeli military officials have told reporters there is no policy to raze civilian neighborhoods wholesale. They say they are attacking sites used by Hamas, blowing up underground tunnels and other military targets.

But Israeli leaders have suggested it could go further than that.