Air-raid sirens were sounded in Jerusalem on Friday, marking the first time the holy city has been targeted by rocket fire from Gaza.
Initial reports from Israeli television said three rockets had landed in the area of Gush Etzion, south of Jerusalem.
The alarms come just a day after Gaza rockets landed on the outskirts of Tel Aviv. Previously, Palestinian rocket fire has been largely confined to an area closer to the Gaza Strip, leaving Israel's major population centers largely unscathed.
Israel has authorized the call-up of roughly 16,000 reservists in a sign that a ground invasion of Gaza may be imminent.