An IDF spokesman said that during the day Sunday the IDF attacked over eighty terrorist targets, including rocket launching infrastructure and smuggling tunnels.
The IDF targeted the head of Hamas's rocket program, Yahiya Abiya on Sunday afternoon in an airstrike. The attack was directly ordered by Chief of Staff Lt.-Gen. Benny Gantz.
Army sources say that Abiya was directly responsible for the majority of rockets that have been fired on Israel.
The IDF confirmed communications infrastructure in the northern Gaza Strip used by the Hamas terrorist organization was also attacked.
According to Palestinian sources, strikes throughout the day killed at least 11 Palestinian civilians in the Gaza Strip, the highest death toll in a single incident in five days of fighting.
The casualties included nine children and five women in the attack on a three-story building, medics say. The house reportedly belonged to a Hamas official.
Ma'an also reported that the number of Palestinian casualties rose to at least 72 on Sunday, with hundreds wounded.
Rescue workers were still at the site searching for people who might be buried under the rubble.
The airforce has taken every measure possible to try and avoid harming Palestinian non-combatants, including precision strikes and issuing warnings to civilians. Hamas often employs the tactics of using civilians as human shields.
Prime Minister Benjamin Netanyahu said earlier that he had assured world leaders that Israel was doing its utmost to avoid causing civilian casualties in the military showdown with Hamas.
On Sunday morning, the Erez and Kerem Shalom crossings were opened to allow the passage of goods and humanitarian aid to the Gaza Strip.
Palestinians in the Gaza Strip fired dozens of rockets toward a number of Israeli cities Sunday, striking among others, Beersheba, Ashdod, Ashkelon and Sderot. At least ten civilians were injured.
Over 1200 terror targets have been hit in Gaza since the beginning of
the operation on Wednesday. Additionally, over 520 Palestinian rockets exploded in Israeli territory. A small percentage of those exploded in urban areas.
The Israeli Navy bombarded targets from the sea and an air raid targeted a building in Gaza City overnight Saturday housing media agencies and television stations, wounding six journalists from Iran's PressTV and al-Quds television, a station Israel sees as pro-Hamas, witnesses said.
IDF Spokeswoman Avital Leibovich on Sunday briefed foreign press about the media building strike, saying "we obviously know there are journalists in the building, so we did not attack any other floor," according to an audio recording of the briefing.
The IDF said it was targeting a "transmission antenna used by Hamas to carry out terror activity." Britain's Sky News and Hamas's Al-Aqsa TV were damaged in the attack. Journalists from Al-Aqsa TV and Iran's PressTV were injured.
Leibovich added that her advice to journalists in Hamas-administered Gaza, is to "stay away from any Hamas positions, Hamas sites, or Hamas posts for their own safety."
Two other predawn attacks on houses in the Jebalya refugee camp killed two and wounded 12 other people, medical officials said. According to the Bethlehem-based Ma'an News Agency, the IAF also struck several targets connected to the Popular Resistance Committees and Hamas's military wing.
More than 550 of the approximately 1000 rockets fired from Gaza have hit Israel, killing three people and injuring dozens.
Israel unleashed its massive air campaign on Wednesday, killing Hamas military chief Ahmed Jabari with the declared goal of deterring gunmen in the coastal enclave from launching rockets that have plagued its southern communities for years.
Reuters contributed to this report.
Correction: An earlier version of this story reported that the IDF assassinated the head of Hamas's rocket program, Yahiya Abiya on Sunday afternoon in an airstrike. It is unclear whether Abiya was assassinated in the targeted strike.