"We will find Sinwar and will eliminate him," Gallant told a news conference, as Israeli forces fought street battles with Hamas militants inside the Palestinian territory.

"I tell the residents of Gaza - if you reach him before us, it will shorten the war."

Soon after the war between Israel and Hamas erupted, Israel said that Sinwar was a "dead man walking," and that he and the leader of the group's armed wing, Mohammed Deif, were the army's top targets.

Security sources outside Gaza say Sinwar and Deif are now holed up in a network of tunnels built to resist the ferocious bombardment Israel launched in response to the October 7 attacks by Hamas which killed more than 1,400 people, mainly civilians.

Gallant said Israeli forces were fighting "hard" inside Gaza.

"We have finished and completed the encircling (of Gaza City). The IDF (Israeli army) forces are operating from south and north (of Gaza City) and have entered populated areas," Gallant said.