At least 24 Palestinians were killed overnight as Israel launched a ground offensive in Gaza, with the initial aim of destroying the underground tunnels into the heavily populated area.
Israeli air raids on five areas within Gaza have killed nine Palestinian militants.
Israel has bombed dozens of sites in the Gaza Strip and killed a Palestinian during raids in the West Bank after the bodies of three kidnapped Israeli teenagers were found near the city of Hebron.
Israelis go to the polls on Tuesday in a general election that is expected to result in current Prime Minister Benjamin Netanyahu retaining his office, but as head of a joint right-wing Likud-Yisrael Beitenu list.
Israel assassinated the military chief of Hamas, Ahmed Said Khalil al-Jabari, on Wednesday, causing the conflict to escalate and Hamas warning that Israel have opened the “gates of hell”.