The international community has called for an end to the escalating conflict.
Earlier, Israeli air strikes in Gaza killed 10 people in a refugee camp and, separately, destroyed a building that housed foreign media organisations.
Hundreds of Palestinian rockets were fired into Israel, causing one death.
The UN Security Council will meet on Sunday to discuss the situation. US envoy Hady Amr has arrived in Tel Aviv to take part in talks with Israeli, Palestinian and UN officials, and reinforce what US diplomats said was the need for a "sustainable calm".