"We are in the heart of Gaza City," Gallant said at a press conference. "Gaza is the largest terrorist base ever built."

"We are going to destroy Hamas," he said.

The Israel-Hamas war started on October 7 when fighters from the Islamist group burst out of the Gaza Strip and into southern Israel.

According to Israel, Hamas militants killed some 1,400 people -- mostly civilians -- and seized more than 240 hostages, in the worst attack on the nation since its founding in 1948.

In response Israel has launched a withering assault on Hamas in the Palestinian enclave it rules, home to some 2.4 million people.

The Hamas-run health ministry there says more than 10,300 people -- also mostly civilians -- have been killed by Israel's offensive.

There have been increasing international calls for a ceasefire or "pause" in fighting as the conflict enters its second month.

However Gallant said "there will be no humanitarian truce without the return of the hostages".