In response to an earlier airstrike, Palestinian militants have fired rockets into southern Israel killing one person in Ashkelon.
The attack came from Gaza, after seven members of the group Islamic Jihad were killed.
Israeli authorities say at least 20 rockets were fired, hitting other areas, including the port city of Ashdod.
Islamic Jihad is not linked to Hamas.
Hamas leader Mahmoud Al-Zahar said Israel’s assault was unjustified: “The resistance has the right to defend itself. I think Israel is the only loser in all these criminal actions, because there are no reasons to carry out an attack against any Palestinian leader in Gaza while people are celebrating the release of prisoners.”
The airstrikes were carried out by the Israeli Defence Forces, and are believed to be in retaliation for a rocket that hit Ashdod on Wednesday – an act which was blamed on Islamic Jihad. The Israeli military say the group was planning more attacks.