The death toll from airstrikes has risen to 256 as Israeli warplanes on Sunday kept bombing targets in the Gaza Strip, including a government building.
In a statement, the Israeli army said that its "forces continue their attacks throughout the Gaza Strip."
"Fighter jets recently attacked a military infrastructure at the home of the head of the intelligence department of the terrorist organization Hamas," the army added.
Israeli fighters continue to launch raids and destroy homes in various areas of Gaza, an Anadolu Agency (AA) correspondent reported.
Israeli aircraft destroyed the headquarters of the Government Labor Directorate in Gaza, affiliated with the Islamic Resistance Movement
Hamas, after targeting it with at least one missile, according to the correspondent.
Hamas launched Operation Al-Aqsa Flood on Saturday and said the surprise attack was in response to the storming of the Al-Aqsa Mosque and increased settler violence. It said it fired rockets and captured many Israelis.
Hamas chief Ismail Haniya earlier said their "heroic" attack was in response to violence by Israeli forces and illegal settlers on Palestinian civilians, and storming of Al Aqsa Mosque.
The Israeli army, in turn, said it initiated Operation Swords of Iron in the Gaza Strip, a "large-scale operation to defend Israeli civilians against the combined attack."
Israeli Prime Minister Benjamin Netanyahu and other Israeli officials said the country is at war.
At least 750 Israelis have been missing since fighting broke out on Saturday morning, local media reported early Sunday.
At least 256 Palestinians have been killed and 1,788 others injured in the attacks, according to medical sources in Gaza, while the Israeli death toll climbed to 300.
More than 3,000 rockets have been launched by Hamas toward Israel since Saturday morning, according to the Israeli army.