The remains of a rocket, launched from Gaza into southern Israel.
The Israeli military said two rockets fired from Gaza struck southern Israel on Wednesday, causing no casualties, hours after Israeli planes launched an air strike in the north of the territory.
Israel launched the air strike after three Gaza rockets hit its south the day before.
An al Qaeda-linked group, Magles Shoura al-Mujahadeen, claimed responsibility for the Tuesday strikes.
Speaking from Gaza, a Hamas spokesman accused Israel of escalating the situation with the air strikes.
It's the most serious outbreak of cross-border hostilities since a ceasefire ended an eight-day war in November.
Hostilities flare along Israel-Gaza border (0:48)
April 3 - Gaza cross border violence on the rise for the first time since a ceasefire ended an eight-day war in November. Sarah Sheffer reports. ( Transcript )