Across the border, sirens sent Israelis running to shelters as the blasts of rocket interceptions sounded overhead, and Jonathan Conricus, spokesman for Israeli military, said Israel was prepared to intensify its attacks.
The Israeli strikes claimed at least three Palestinian lives, including a 14-month-old baby and her pregnant mother, according to the Gaza health ministry.
Quoting Palestinian sources Press Tv reported that the Israeli airstrikes had left two people dead and several others wounded in northern Gaza.
Two Palestinians were also reportedly killed during the so-called Palestinian "March of Return" protests along the Gaza border. An Israeli air strike in retaliation killed two militants from the Islamist Hamas group which governs Gaza.
Earlier on Saturday, Palestinian militants fired about 100 rockets into southern Israel, damaging a house, Israeli authorities said. Netanyahu is now engaged in tough negotiations to form a new government following last month's election, while Israel is due to host the Eurovision song contest in Tel Aviv from May 14-18. More than 200 Palestinians and an Israeli soldier have been killed in the border protests.
Approximately 90 rockets have been fired by Gaza militants towards Israel in the space of an hour Saturday morning, according to the Israel Defense Forces (IDF).
Israeli artillery struck on watchtowers east of al-Tuffah neighbourhood north of Gaza City and on a watchtower and a military site in the Sofa area between Rafah and Khan Younis in the Strip's south.
Israeli officials said a 50-year-old woman was severely wounded by rocket fire, while a teenage boy was mildly hurt as he ran for cover. Tanks were also targeting militants, it said.
The flare-up marked the first Israeli strike in more than a month of relative calm that followed the unofficial deal.
Israel says this is needed to stop weapons reaching Gaza.
The current round of violence started on Friday when two Israeli soldiers were hit by sniper fire from the Gaza Strip.
It also said that a rocket had hit a house in the town of Kissufim that lies just two kilometres from the edge of Gaza.
Palestinians have participated in regular demonstrations and clashes along the Gaza border for more than a year, calling on Israel to ease its crippling blockade of the enclave.