Israel said Wednesday its troops retook part of a corridor that bisects Gaza, and its defense minister warned that attacks would intensify until Hamas frees dozens of hostages and gives up control of the territory.

Israel said it recaptured an area from which it withdrew in the recent cease-fire, in the most significant ground operation since the truce with Hamas collapsed.

Israeli forces have resumed "focused ground operations" in the "center of the Gaza Strip," over the past 24 hours, according to the Israel Defense Forces.

Israel said it sent ground troops back into the center and south of the Gaza Strip, expanding a military operation that began with airstrikes a day earlier that Palestinian authorities said killed hundreds of people.