Israeli tanks deepened their incursions into the Shujaya suburb in eastern Gaza City for a fifth day, and tanks advanced further in western and central Rafah, in southern Gaza near the border with Egypt, residents said.
Witnesses reported constant Israeli tank fire in the district after Prime Minister Benjamin Netanyahu said Israeli forces were engaged in a "difficult fight".
The head of the Gaza Strip's biggest hospital said on Monday, after being freed from more than seven months of detention, that he had been "tortured" by Israel.
Al-Shifa Hospital director Mohammed Abu Salmiya was among dozens of Palestinians released and returned to Gaza for treatment, according to Israeli authorities.
Abu Salmiya said he and other prisoners were put through "severe torture" in Israeli prisons after being detained since the 7 October.