The United Nation's Secretary General has called for an immediate ceasefire as Israel's pounding of Gaza goes into its sixth day.
Ban Ki-moon says he was going to Cairo to join talks about a possible truce.
Sunday in Gaza was the bloodiest day of Operation Pillar of Defence, as Israel said it was targeting the homes of Hamas militants, the BBC reports.
Eighty-six Palestinians and three Israelis have died in six days, as Israel hits Gaza from the sea and air while Hamas militants fire rockets towards Israel.
The Israeli bombardments began last Wednesday following the killing of Hamas military chief Ahmed Jabari. Three Israelis were killed by Palestinian rocket attacks the following day.
Israel's army says it targeted about 80 sites overnight, including militant-owned buildings, weapons storage facilities and police stations, bringing its total to 1350 sites targeted since Wednesday.
Palestinian sources told the BBC 18 people had been killed in the raids.
They say one rocket was fired out of Gaza towards Israel overnight, with more rocket fire resuming.
Israeli Prime Minister Benjamin Netanyahu said on Sunday he was ready to expand the operation, after Israel authorised the mobilisation of up to 75,000 army reservists.
Egyptian President Mohammed Mursi has said an Israeli ground invasion would have "serious repercussions", saying Egypt would never accept it "and neither will the free world".
The Arab League, which met in emergency session in Cairo on Sunday, is sending a delegation of foreign ministers to Gaza on Tuesday.