Israel has urged thousands of Palestinians in eastern and northern parts of Gaza to evacuate their homes as it continues air strikes.
The Israel Defense Forces (IDF) said it had used recorded telephone messages to warn some 100,000 residents of Gaza to leave their homes before 8am (local time) on Wednesday, reports BBC.
The continuation of air strikes comes after Israeli Prime Minister Benjamin Netanyahu said he had "no choice" but to step up the military campaign.
Israeli attacks were halted for six hours, but resumed after militants continued to fire dozens of rockets.
Israel, which had its first fatality on Tuesday, said senior Hamas militants had died in strikes on Gaza overnight.
Palestinian officials say Israeli raids have killed 204 people so far, including ten overnight into Wednesday.
Israel launched its Operation Protective Edge on 8 July. Its stated objective is to halt Palestinian rocket attacks on Israel, but the United Nations says the majority of those killed in Gaza are civilians.