Hamas has dismissed as a sign of weakness warnings from Israeli Prime Minister Benjamin Netanyahu for Gaza residents to leave any site where Palestinian fighters are operating, saying the locations could be attacked.
In a statement on Sunday, Sami Abu Zuhri, a Hamas spokesman, said: "The [Israeli] occupation has failed in confronting the resistance in the field, and has resorted to threats of assassination and other threats designed to scare us.
"But the will of our people will not be broken."
Speaking earlier, Netanyahu said: "I call on the inhabitants of Gaza to vacate immediately every site from which Hamas is carrying out terrorist activity. Every one of these places is a target for us."
Netanyahu's comments came as Israeli air strikes pounded the Gaza Strip on Sunday, killing at least 16 people.
Hours after Netanyahu spoke, a strike killed a mother and three children from the same family in northern Gaza, medics said. The strike hit a home near Jabalia.
Earlier in the day, strikes killed a one-year-old girl and a 17-year-old boy, Gaza health ministry spokesman Ashraf al-Qudra said.
A cluster of four homes were destroyed by strikes in Khan Younis, along with a strike on a car which killed Mohammedal-Ghoul, described by Israel as a Hamas official responsible for "terror fund transactions".
Israel said it hit 20 targets in Gaza on Sunday morning, while Palestinian fighters fired at least 20 rockets rounds at Israel, the army said. Sixteen Palestinians were reported killed.
On Saturday, the Israeli military warned residents of Al Zafer Tower, a 13-storey building to leave, shortly before launching air strikes. It said the tower had housed a Hamas command centre.
The residential block in the centre of Gaza City collapsed wounding 22 people, including 11 children. Local residents said the building housed 44 families.
At least 11 Palestinians were killed in a series of Israeli strikes on Saturday.
The Israeli prime minister said that his Gaza offensive would continue as long as necessary, a day after an Egyptian call for a ceasefire and new truce talks.
"Operation Protective Edge will continue until its aims are achieved... it may take time," he said of the Gaza Strip operation launched on July 8, in remarks broadcast by public radio.
Netanyahu also added a veiled warning to neighbouring Lebanon and Syria after overnight rocket fire into Israel.
"There is not and will not be any immunity for anyone who fires at Israeli citizens, and that is true for every sector and every border," he said.
Amid the violence, Palestinian President Mahmoud Abbas held talks with senior officials of the Arab League on Saturday night in the Egyptian capital, Cairo. Earlier that day, Abbas stressed his willingness to achieve a long-term ceasefire between the two enemies.
The Egyptian foreign ministry on Saturday urged Israel and Hamas to resume indirect talks and agree to an open-ended ceasefire.
Palestinian health officials say 2,108 people, most of them civilians, have been killed in the deadliest fighting since the 2005 end of the second intifada. Three Israeli civilians, a Thai national and 64 soldiers have also been killed.