Israel's bombardment of the Gaza Strip has killed 28 Palestinians in the bloodiest day so far of the five-day-old conflict, as diplomatic efforts to broker a truce intensify.
United Nations Secretary General Ban Ki-Moon has called on Israel and Hamas to reach an immediate ceasefire, urging them to co-operate with Egyptian-led efforts to negotiate a truce.
But the Israelis say they are prepared to step up their military operation if Hamas continues to launch rockets into Israel.
Speaking at a cabinet meeting on Sunday, Prime Minister Benjamin Netanyahu said Israel was ready to "significantly expand" its operation, with its soldiers ready "for any activity that could take place".
Shelling and bombing continued through the night with one blast destroying a Hamas police headquarters.
Ten people died in one Israeli air strike on a house in Gaza, the highest civilian death toll in a single incident during the conflict.
Palestinian medics say three women, six children and one man were killed in the attack on the home of Hamas official Mohamed Dalou on Sunday, with Hamas saying the total killed on Sunday is 28 .
The BBC says the medics say 80 Palestinians have died since 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.
The number of injured and dead across Gaza is mounting, emergency services are at full stretch and hospitals are struggling also, the BBC reports.
In Israeli cities, people were again scrambling to reach bomb shelters after rocket fire resumed following an eight-hour break. The damage inflicted is not on the same scale - but on both sides civilians are suffering.
"We are exacting a heavy price from Hamas and the terrorist organisations and the Israel Defence Forces are prepared for a significant expansion of the operation."
The Israeli army says 105 missiles fired from Gaza hit Israel on Sunday, while 41 were intercepted by its Iron Dome missile defence system, including at least one over Tel Aviv.