Palestinian militants have launched another barrage of rockets into southern Israel, hours after firing more than 25 mortar bombs across the border.
There were no casualties reported in Israel after the morning and afternoon salvos.
Several of the projectiles, the military said, were intercepted by the Iron Dome anti-missile system. Israeli aircraft were carrying out raids against militant groups' facilities in the Gaza Strip in response to the attacks.
It is unclear which Palestinian militant group is responsible for the mortar fire, though both Hamas and Islamic Jihad applauded the action.
One of the mortars landed in an Israeli kindergarten, Israeli media reported, while the Hamas-run Gaza Education Ministry said a school in the central Gaza Strip was badly damaged by the Israeli strikes.
Israeli Prime Minister Benjamin Netanyahu said his army will react "forcefully" to dozens of mortars fired at Israel.
"(The Israeli army) will respond with great force to these attacks, and Israel will exact a heavy price from anyone who tries to harm it, and we see Hamas as responsible for preventing these attacks against us," Netanyahu said in a statement.
Hamas seized control of the Gaza Strip in 2007.
Separately, a coalition of Palestinian protest organisers are attempting to sail a boat from the Gaza Strip to international waters to break Israel's naval blockade.
Israel prevents any Gaza boats from leaving a restricted fishing zone that spans a number of kilometres, and has previously shot at Gaza fishermen to enforce the blockade.
