A five-hour ceasefire was observed on the request of the United Nations for humanitarian reasons, but hostilities quickly resumed after it ended.
Three children were killed in an Israeli airstrike in the heart of Gaza city. Two Palestinians were injured another airstrike.
At least three mortar shells were fired from Gaza during the ceasefire, and the Israeli military said a soldier was injured by an explosion during an "operational activity" near southern Gaza. Troops responded with mortar fire, the Israel Defense Forces said.
Despite those incidents, UN Secretary-General Ban Ki-moon said both sides had "mostly respected" the ceasefire.
UN Special Coordinator for the Middle East Peace Process Robert Serry had asked Israel for a humanitarian ceasefire following an incident in which four Palestinian children were killed on a beach in Gaza.
The two sides agreed to the ceasefire to allow Palestinians to stock up on food, water and other necessities.
During the lull in fighting, air raid sirens went off briefly in southern Israel and the truce appeared to be generally holding.
Palestinians rushed to shops and banks as the five-hour truce agreed by Israel and Hamas came into force.
"Should the humanitarian window be exploited by Hamas or other terror organisations for the purpose of launching attacks against Israeli civilian or military targets the IDF will respond firmly and decisively," the Israel Defense Forces said in a statement.
An earlier effort to permanently stop the fighting failed when Israel resumed airstrikes following a brief, one-sided ceasefire brokered by Egypt. While Israel paused for six hours, Hamas rejected the deal and continued firing rockets.
Hamas leaders said they had not been consulted, and complained the deal did not address their demands for greater freedom for Gaza's 1.8 million residents.
At least 233 Palestinians have been killed and close to 1,700 have been injured since Israel began its anti-Hamas military operation July 7, according to Palestinian health officials. One Israeli death has been reported.
Before announcing the temporary truce today, Israeli tank fire killed three people in Rafah town in Gaza. Their deaths came after another seven people were killed overnight.
The one fatality on the Israeli side so far was a man killed on Monday after being hit by a mortar shell at the Erez border crossing.
Meanwhile, Israel's Foreign Minister Avigdor Lieberman and Hamas have denied earlier reports of a truce deal to end fighting in Gaza between Israel and Palestinian militants.
Lieberman said the reports were "as of now incorrect", and Hamas, which controls Gaza, said talks in Egypt were ongoing.
Palestinian President Mahmud Abbas met Egyptian President Abdel Fattah al-Sisi today amid intensifying efforts to end the fighting in Gaza.
Abbas held talks in Cairo yesterday, as did Quartet envoy Tony Blair, in an effort to reach a mutually acceptable deal.
Abbas met with Hamas official Musa Abu Marzouk, and Egypt, Qatar, Turkey, and even Tunisia and France were reportedly involved in efforts to quell the violence.
President Barack Obama also backed Egypt's efforts to broker a ceasefire, offering the US' full diplomatic support.