Some 643 Palestinians, many of them children and civilians have died in the conflagration, including a seven-year-old hit by a shell in southern Gaza early Wednesday, Palestinian medical sources in Gaza said.
Clouds of black smoke hung over the densely populated enclave, with the regular thud of artillery and tank shells filling the air.
According to the IDF, 30 militant gunman had been killed overnight, bringing the total to 210 since the offensive started.
Airstrikes killed a six-month-old infant and a 24-year-old Palestinian in northern Gaza Tuesday evening, in addition to a Palestinian bombed on a motorcycle elsewhere in the territory, Palestinian health officials said.
The IDF said it had killed 186 terrorists.
With Israeli shells and bombs hitting Gaza day and night, thousands of people have fled districts close to the border. The main UN agency in Gaza, UNWRA, said almost 102,000 people had taken shelter in 69 of its schools.
UNRWA said it found rockets hidden in a vacant Gaza school near two buildings housing refugees who have fled, in the second such instance of militants accused of storing weaponry in a school during the latest offensive.
An UNRWA statement said staff were removed from the building where the rockets were found adding that it "strongly and unequivocally condemns the group or groups responsible."
The IDF said that 20 terrorists were killed in over 100 airstrikes overnight Monday, bringing the overall number of tragets hit by Israel was 3,200. Twenty eight terrorists have been arrested since the IDF launched its ground incursion into the Gaza Strip, a senior military official said.
The military source further said that 100 targets were attacked in the Shuja'iyya neighborhood.
On Tuesday morning, civil defense crews with a crane parked outside the Salam building in Gaza City, which was hit in an Israeli airstrike.
The tower block's top five floors had collapsed onto its bottom four floors. The leg of a person was visible from the street, lying on a piece of rubble caked with streams of dried blood.
Air strikes set off huge explosions that turned the night sky over Gaza City orange. The sound of the blasts mixed with the thud of shelling, often just seconds apart, and the pre-dawn call to prayer from mosque loudspeakers.
Early Tuesday, IAF aircraft hit more than 70 targets in the Gaza Strip, AP reported, including the home of the late leader of Hamas' military wing, five mosques and a football stadium, said Gaza police spokesman Ayman Batniji.
Batniji said tank shells damaged several houses along the eastern border of the territory and that at least 19 fishing boats were burned by Israeli navy shells fired from the Mediterranean.
A husband and wife from Gaza were evacuated in moderate condition to Israel's Tel HaShomer Hospital in Ramat Gan. A 14-year-old Gazan teen in moderate condition was also evacuated with them and a six-year-old girl who was lightly wounded.
Israel's death toll also rose to 30, with two soldiers killed in the past day of fighting, the IDF said. The total includes two civilian killed by rocket fire.
Violence also spread to the West Bank, where medics said soldiers shot and killed a Palestinian man while dispersing protesters throwing stones at a military jeep.
Roi Kais, the Associated Press and Reuters contributed to this report