A morgue worker carries the body of a Palestinian child killed in the Israeli bombardment on Saturday. AP

Israel-Palestinian group Hamas war entered a fourth month Sunday, with fears mounting that the conflict could spread into neighbouring Lebanon.

Six people were killed early on Sunday during an Israeli raid in Jenin in the occupied West Bank, the Palestinian health ministry said, with witnesses reporting that Israel had also carried out air strikes in Gaza's main southern city of Khan Yunis.

Israel's army said late on Saturday it had "completed the dismantling of the Palestinian group Hamas’s framework in the northern Gaza Strip" and its forces would now focus on central and southern areas of the territory.

The prospect of a wider regional war loomed with army spokesman Daniel Hagari warning that Lebanon's Iran-backed Hezbollah group was "dragging Lebanon into an unnecessary war".

The group fired more than 60 rockets at an Israeli military base on Saturday in response to this week's killing in Beirut of Hamas's deputy leader.

A Palestinian child wounded during the Israeli bombardment of the Gaza Strip receives treatment on Sunday. AP

Israel's Prime Minister Benjamin Netanyahu vowed that Israel would continue its campaign to "eliminate Hamas, return our hostages and ensure that Gaza will no longer be a threat to Israel".

Netanyahu was under growing pressure on Saturday with demonstrators gathering in Tel Aviv's Habima Square to call for early elections and the resignation of his government.

"Bibi Netanyahu and all the rest of his idiots are ruining Israel and they are destroying everything we hoped and dreamed of," Shachaf Netzer, 54, told the media.

"Everybody here wants an election."

'Uninhabitable'

AFP correspondents reported Israeli strikes on Saturday in the southern Gaza city of Rafah, where hundreds of thousands of people have sought shelter from the fighting.

A picture shows flares fired by Israeli soldiers over Khan Yunis in the southern Gaza Strip on Sunday. AFP

Victims of the bombardment were brought to the European Hospital in Khan Yunis, where relatives and mourners gathered.

One of them, Mohamed Awad, wept over the body of a 12-year-old boy and counted the deaths in his family.

"My brother, his wife, his children, his relatives and the brothers of his wife -- there are more than 20 martyrs," Awad, a journalist, told the media.

Civilians in the Hamas-ruled Gaza Strip have borne the brunt of the conflict as the scale of the destruction has triggered mass displacement and a deepening humanitarian crisis.

With swathes of the territory reduced to rubble, UN humanitarian chief Martin Griffiths on Friday said "Gaza has simply become uninhabitable".

An Israeli artillery unit fires near the Israel-Gaza border in southern Israel on Sunday. Reuters

The World Health Organization says most of Gaza's 36 hospitals have been put out of action by the fighting, while remaining medical facilities face dire shortages.

International aid group Doctors Without Borders said it had evacuated its staff from Al-Aqsa hospital in central Gaza after a bullet penetrated a wall in the intensive care unit.

"The situation became so dangerous that some staff living in the neighbouring areas were not able to leave their houses because of the constant threats of drones and snipers," said Carolina Lopez, the group's emergency coordinator at the hospital.

Agence France-Presse