The Israel Defense Forces said it is making every effort to prevent civilian deaths during its current operation in the Gaza Strip.

The army has continued its policy from the Second Lebanon War of dropping leaflets over civilian areas notifying them of their intent to bomb the area.

The IDF dropped leaflets on Gaza City on Saturday, amid heavy aerial bombing, warning of a wider offensive.

"The IDF [Israel Defense Forces] is not working against the people of Gaza but against Hamas and the terrorists only," the leaflets said in Arabic. "Stay safe by following our orders."

On Sunday, it dropped additional leaflets urging Gaza residents to report the whereabouts of Hamas fighters, even providing a phone number to call.

"You can call the numbers listed below to inform us about the locations of rocket launchers, warehouses, tunnels and terrorist groups operating in your area, said the leaflet, promising confidentiality guaranteed."

Still, a Palestinian medical official said that most of the 21 Gazans killed Sunday were noncombatants, including four members of one family killed when a tank shell hit their home near Gaza City.

The army, meanwhile, says Hamas fighters are wearing civilian clothes and endangering civilians by operating out of heavily populated residential areas.