Israeli marines clashed with Hamas gunmen Sunday in the first reported ground incursion in the latest Gaza offensive. It follows a heavy night of violence during which 18 members of the same family were killed in the deadliest single attack on the besieged enclave in days of shelling.

A Palestinian woman and a girl, aged 3, were killed in Israeli raids early on Sunday, Gaza's Health Ministry said. Hours earlier, the ministry said the house of Gaza's police chief was bombed by the air, resulting in many casualties.

The Israeli army said at least four soldiers were "lightly injured" on Sunday, as they attacked a site in northern Gaza the army said was being used to launch long-range rockets.

Giving details of the naval commando operation early on Sunday, Lieutenant Colonel Peter Lerner, an Israeli military spokesman, said four members of the force were wounded in exchanges of fire with Hamas fighters.