The strikes were in response to an overnight rocket attack — the first firing from Gaza since a missile hit a house in the city of Beersheba a week ago, threatening to spark another full-fledged confrontation.
Egypt and the United Nations are trying to mediate a long-term truce between Israel and Hamas, the Islamist militant group that rules Gaza.
Israel and Hamas have fought three wars over the past decade. Tensions have been rising over the weekly border protests Hamas has organized to try to ease a crippling Israeli-Egyptian blockade.