Israel starts pounding Gaza City

Israel hammered Gaza City and its outskirts overnight, residents said Thursday, as the military announced it had taken the initial steps in its push to capture Hamas's last major stronghold.

The newly approved plan authorises the call-up of roughly 60,000 reservists, deepening fears the campaign will worsen the already catastrophic humanitarian crisis in the Gaza Strip.

"We are advancing with the efforts toward operations in Gaza City," military chief Eyal Zamir told troops on Thursday.

"We already have troops operating on the outskirts of the city, and more forces will join them later on."

Israel's plans to expand the fighting and seize Gaza City have sparked international outcry as well as domestic opposition, with the Red Cross joining the condemnation on Thursday, calling the moves "intolerable".

Ahead of the offensive, the Israeli military said the call-up of the reservists would begin in early September, adding the second phase of operation "Gideon's Chariots" had begun.

Gaza City residents described relentless bombardments overnight.

"The house shakes with us all night long — the sound of explosions, artillery, warplanes, ambulances, and cries for help is killing us," Ahmad al-Shanti told AFP.

"The sound is getting closer, but where would we go?"

Another resident, Amal Abdel-Aal, said she watched the heavy strikes on the area, a week after being displaced from her home in Gaza City's Al-Sabra neighbourhood.

"No one in Gaza has slept — not last night, not for a week. The artillery and air strikes in the east never stop. The sky flashes all night long," she added.

Gaza civil defence agency spokesman Mahmud Bassal said air strikes and artillery fire overnight targeted areas to the northwest and southeast of the city.

A group of AFP journalists near Israel's border with Gaza also witnessed an air strike by a fighter jet on the northern outskirts of Gaza City on Thursday afternoon, with a massive explosion followed by a large plume of smoke rising into the sky.