The IDF and the Shin Bet domestic security service said Wednesday that 16 high-ranking members of the Hamas terror group, including a senior commander and weapons developers, had been killed in Israeli targeted attacks on Gaza City and Khan Yunis.
The dead were members of the Hamas high command and close associates of Mohammed Deif, head of the terror group's military wing who has himself survived numerous Israeli attempts on his life.
According to the Shin Bet, the casualties included Bassim Issa, veteran Hamas brigade commander for Gaza City; Jomaa Tahla, the Hamas cyber and missile technology chief and 13 members of the group's weapons manufacturing staff.
Israeli military officials called the killings a groundbreaking, complex operation whose details were yet to be revealed.
Palestinian sources confirmed an Israeli attack on a vehicle in Khan Yunis in the southern Gaza Strip, saying at least one of the occupants had been killed.
The Israeli attacks were swiftly followed by a barrage of some 50 rockets fired from Gaza at the southern cities of Ashkelon and Ashdod and their environs.
Israeli media quoted military sources as saying that they expected further rocket fire on central Israel as a result of the killings.
Also Wednesday, the IDF attacked Hamas and Islamic Jihad weapon production sites in the northern Strip that were located inside civilian areas.
"The IDF is taking every precaution to avoid harm to civilians and their property but will continue to operate in Gaza as long as is necessary," the military said.
Prime Minister Benjamin Netanyahu said while visiting Wolfson Medical Center in Holon that the targeted killing of Hamas top officials was "only the beginning".
He said earlier that Israel would response with increasing force to the continued rocket and mortar fire directed at civilian communities along the border. But, the prime minister said, he would not "go into details here."
"From here I am heading to a meeting with the IDF chief of staff and Air Force commander at the Kiriya," Netanyahu said during a trip to the northern city of Acre, referring to the Defense Ministry headquarters in Tel Aviv.
"We will have a security cabinet meeting later, there are serious developments," he said. "We will respond with increasing force" to the attacks from Gaza.
Wednesday marked the third consecutive day of rocket fire from Gaza at Israeli population centers, in a round of attacks that began Monday evening with a volley launched at the Jerusalem area after days of clashes in the city between Palestinians and Israeli security forces.
That initial attack was followed by ongoing, near continuous heavy rocket fire on southern communities, which left two dead in Ashkelon and dozens wounded. And on Tuesday night, two massive salvos were fired at central Israel, killing one person in Rishon Lezion and a father and his teenage daughter in Lod.
Israel has responded to the rockets with repeated air and artillery strikes on what it says were terror targets in Gaza.
Palestinian officials say at least 48 people have been died in the Israeli strikes, including 14 children, and that 304 people had been wounded. Israel says that some of the dead were killed by scores of rockets that misfired and struck Gaza.
Israel's security cabinet was set to meet Wednesday at 5.30pm to discuss an expansion of its military operations against the Gaza terror groups.
Defense Minister Benny Gantz was also to request cabinet approval for a two-week extension to the emergency order for areas 80km or less from the Gaza border.
The order allows local officials to close schools and businesses in order to protect the civilian population.
Meanwhile Islamic Jihad said Wednesday it was preparing further rocket attacks.
"We fired 100 rockets at Tel Aviv and other cities and are prepared to fire more," the terror group said, referring to the barrages on the center of Israel on Tuesday night.
"We will continue our struggle and not back down. Gaza is the sword of Jerusalem," the Iranian-backed group said.