Gaza City - Israeli ground troops pushed deep into southern Gaza City Thursday, advancing as far as 1.5 kilometres from the city centre amid heavy tank shelling, residents said.

The ground forces were "very close" to the city's Islamic University and its United Nations headquarters, a local Deutsche Presse-Agentur dpa correspondent said, adding that he was sheltering with his family inside a home in the central Rimal neighbourhood with the troops fighting nearby.

Backed by tanks firing large numbers of shells, the Israeli troops, concentrating in the southern Tel el-Hawa neighbourhood just south of Rimal, fought heavy battles with local militants.

Residents in Tel el-Hawa were panicking in their residential buildings, some of them high-rises, while keeping doors and windows shut, and calling on the international aid organizations to evacuate them.

Ambulances were unable to reach the area amid the heavy fighting. (dpa)