Gaza militants fired two rockets into southern Israel on Wednesday evening in the latest of a wave of tit-for-tat fire across the border, but Israeli police told AFP that nobody was injured.
On Wednesday morning the Israeli air force hit targets in the northern Gaza Strip, also without causing casualties.
Palestinian security sources said the air strike hit a training camp in Beit Lahiya which was used by militants from the Ezzedine al-Qassam Brigades, the armed wing of the ruling Hamas movement.
A statement from the Israeli military described the target as "a terror tunnel" and said that it was attacked "in response to over 40 rockets that were fired at Israel this week."
A small group of radical Salafists had claimed early on Wednesday the rocket fire in a statement sent to AFP, saying it was in response to recent air strikes on Gaza.
Earlier this week, the armed wings of Hamas and Islamic Jihad fired a barrage of projectiles at southern Israel a day after the air force raided the southern city of Rafah, targeting two men whom the military said were global jihad activists.
The two were critically wounded in the strike and one later died of his injuries. Another eight people were wounded, among them five children.
Monday's rocket fire by Hamas and Islamic Jihad militants marked a rare show of force given that the two group normally observe a de facto truce on rocket fire on Israel.
The last time Hamas militants fired on Israel was during a flareup in June when militant groups fired more than 150 rockets, wounding five people, and Israel hit back with air strikes that killed 15 Palestinians.