The death toll is mounting on both sides after three days of cross-border violence between Israel and militants on the Gaza strip - rockets and missiles from Gaza killed four civilians in Israel, and Israeli strikes killed 19 Palestinians, more than half of them civilians.
The most intense clashes in years have so far left at least four Israelis and 23 Palestinians dead, BBC reports.
The Israeli army says more than 600 rockets have been fired into Israeli territory since Saturday, while it has hit 320 targets in response.
The rocket barrage from Gaza began on Saturday morning. Israel's Iron Dome missile defence system shot down dozens of the rockets, but a number of homes in Israeli towns and villages were hit.
According to Reuters, two Palestinian officials and a TV station belonging to Hamas, Gaza’s Islamist rulers, said a ceasefire had been reached at 0430 a.m. (0130 GMT), apparently stopping the violence from broadening into a conflict which neither side seemed keen on fighting.
Israeli officials did not comment on whether a truce had been reached.
Parts of the international community, including the UN, have called for calm.
Reports on Sunday night suggest the UN, Qatar and Egypt are trying to broker a ceasefire.
On Sunday, Israeli Prime Minister Benjamin Netanyahu said he had ordered the military to "continue its massive strikes on terror elements" in Gaza.
Israel has said its air defence has intercepted more than 150 rockets so far. Mr Netanyahu says the country's forces around the strip would be "stepped up with tank, artillery and infantry forces".
As rockets continue to fall in Israel, all schools within 40km (25 miles) of the Gaza strip have been closed and some shelters have opened to the public.
It began on Friday, during protests in Gaza against the blockade of the area - which Israel says is needed to stop weapons reaching militants.
A Palestinian gunman shot and wounded two Israeli soldiers at the boundary fence. Israel retaliated with an air strike that killed two militants.