"Overnight we increased the entry of IDF forces into the (Gaza) Strip, and they joined the forces already fighting there," army spokesman Daniel Hagari said in a televised briefing.

On Friday evening, Israeli armoured forces and infantry began operating inside Gaza in what Defence Minister Yoav Gallant called "a new phase" of the war on the territory's Islamist rulers.

Israeli forces had made several smaller-scale ground incursions inside Gaza before, but the current one has been their longest presence in the territory since violence erupted with a deadly Hamas assault on October 7.

"We're gradually expanding the ground activities and the extent of our forces in the Gaza Strip," Hagari said.