Israel made clear that despite the truce, its military would carry on searching for hidden tunnels used by militants. Hamas and its allies agreed to the terms and there were no reports of major flare-ups through the day.
Kerry, who has been spearheading international efforts to end the fighting, left Cairo overnight and took his diplomatic push to Paris, where he met the foreign ministers of France, Italy, Britain, Germany, Turkey and Qatar.
Read MoreCrunch time for Gaza truce talks
"All of us call on the parties to extend the humanitarian ceasefire that is currently under way,'' French Foreign Minister Laurent Fabius said.
Israel said five more of its soldiers were killed in pre-truce fighting in Gaza, bringing the army death toll to 40 as troops battled militants in the tiny Mediterranean enclave that is home to 1.8 million Palestinians.
Three civilians, including two Israeli citizens and a Thai laborer, have been killed by rockets fired from Gaza.
Stunned residents of Beit Hanoun wandered through destroyed streets lined with damaged houses or mounds of rubble where once whole buildings had stood.
"Pull yourself together, be strong, aren't you used to this by now!'' one man barked at a sobbing younger relative, only to break down himself. "God help us!'' he moaned.
Israeli tanks stood by as people searched through the debris for their belongings, packing whatever they could, blankets, furniture and clothes into taxis, trucks, rickshaws and donkey carts before fleeing the town.
Naser Tattar, director of Gaza's main Shifa hospital, said most of the bodies recovered on Saturday came from Beit Hanoun, Khan Younis and Shejaia, a district east of Gaza City that has witnessed huge clashes between Israeli troops and militants.