An Israeli air strike killed three members of Hamas in Gaza Strip late Tuesday.
Israeli officials say the gunmen had been preparing to launch rockets into Israel.
Medics attended to the victims brought into a nearby hospital.
The strike followed a Palestinian attack that wounded an Israeli army officer.
Israel's policy is to hold Hamas responsible for any attacks from the territory, which the Islamist group has controlled since 2007.
Though hostile to Israel, Hamas has mostly sought to avoid direct clashes as it shores up its rule in the face of more radical challengers and reaches out to potential allies abroad.
