Israeli forces stormed southern Gaza’s main city on Tuesday in what they called the most intense day of combat in five weeks of ground operations against Hamas militants, and hospitals struggled to cope with scores of Palestinian dead and wounded.

In what appeared to be the biggest ground assault in Gaza since a truce with Hamas unravelled last week, Israel said its troops – who were backed by warplanes – had reached the heart of Khan Younis and were also surrounding the city.

We are in the most intense day since the beginning of the ground operation,” the commander of the Israeli military’s Southern Command, General Yaron Finkelman, said in a statement.

He said Israeli forces were also fighting in Jabalia, a large urban refugee camp and Hamas hotbed in northern Gaza next to Gaza City, and in Shuja’iyya, east of the city.

“We are in the heart of Jabalia, in the heart of Shuja’iyya, and now also in the heart of Khan Younis,” he said.

Hamas’ armed wing, the al Qassam Brigades, said its fighters had destroyed or damaged 24 Israeli military vehicles and snipers had killed or wounded eight Israeli soldiers in ongoing clashes in various areas of Khan Younis.

Separately, Gaza health officials said many people were killed in an Israeli strike on houses in Deir al-Balah, north of Khan Younis. Dr Eyad Al-Jabri, head of the Shuhada Al-Aqsa Hospital there, told Reuters at least 45 were killed. Reuters could not reach the area or confirm the toll.