Israel has urged thousands of Palestinians in eastern and northern Gaza to leave their homes as it continues air strikes.
An Egyptian truce initiative on Tuesday failed to halt rocket attacks on Israel by Hamas militants and other groups.
Israel, which had its first fatality on Tuesday, said senior Hamas militants had died in strikes on Gaza overnight.
Palestinian officials say at least 207 people have died in Israeli air raids, including 10 overnight into Wednesday.
Among those reported killed was a five-month-old baby.
An Israeli man was killed by a mortar shell fired from Gaza near the northern border with Israel.
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 have been civilians.