The number of dead includes 180 civilians and the number of wounded has risen to nearly 2,000, Moawiya Hassanei told AFP.
A raid on the house of the Rafah leader of Hamas' armed wing, the Ezzedine al-Qassam Brigades, killed three neighbours, including one woman, he said.
Abu Anas Chabana was not at home at the time.
The house was destroyed and nearby homes damaged.
An air strike on a Jabalia house killed one man and wounded several people, said witnesses.
Israeli F-16 fighters and helicopters could be heard flying over Gaza all night.
An air strike for the first time targeted the justice ministry in Gaza City, wounding, a medical source said.
Also targeted in early Thursday raids were the education ministry, the president's office, legislative council, police headquarters, witnesses said.
A building belonging to a Hamas-linked group was also destroyed in the Maghazi refugee camp in the centre of the Gaza Strip.
Two homes belonging to Hamas militants were destroyed in the central Nusseirat refugee camp, witnesses said. It was not immediately clear if anyone had been killed or injured.
A metalworking shop in Khan Yunis was destroyed in a raid that wounded three, a military source said.
Another metalworking factory was targeted in Gaza City.
Artillery fire from Israeli naval vessels also hit northern Gaza city, the medic said.