Israel's deadliest Gaza air strikes yet kill five children from same family as Palestinian rocket barrage continues

UN Secretary-General Ban Ki-moon says Gaza is 'on a knife-edge'

Smoke billows from buildings following an Israeli air strike in Gaza on July 10, 2014 (AFP/Getty Images)

The exchange of Israeli air strikes and Palestinian rocket fire has continued to escalate into a third day, as health officials in Gaza reported that the deadliest pre-dawn bombardment yet has killed five children from the same family.

Pictures from the embattled district of Khan Younis showed Palestinian police picking through the rubble of two adjacent houses which had been the home to an extended family – eight of whom are now dead, the health ministry said.

The Palestinian death toll has now risen to at least 75, according to a count from Associated Press reporters. There have been no casualties on the Israeli side.

There are fears that the Israeli offensive could be scaled up to a full ground invasion in the coming days. Tanks and armoured personnel carriers have been seen massing close to the Gaza border.

Israel’s military says it is acting to stamp out the persistent barrage of rockets fired on its southern territories by Gaza militants. It said at least 320 had been fired since the campaign began on Tuesday, and defence spokesman Lt Col Peter Lerner tweeted this morning using the hashtag “IsraelUnderFire”.

He said the missile defence system Iron Dome had intercepted rockets launched at the cities of Beersheba and Ashkelon overnight, adding: “We are putting the pressure up every day. Is it leading a to a ground force incursion? I still can't confirm that will actually happen. I can confirm that we are making all necessary preparations in order to be ready for that.”

The UN Secretary-General, Ban Ki-moon, will today address the Security Council to update them on the worst Israeli-Palestinian violence since an eight-day war was fought in 2012.

A man inspects the aftermath of what police said was an air strike on the house where militant Hafez Hamad and five other people were killed, in the town of Beit Hanoun in the northern Gaza Strip July 9, 2014 (Reuters)

He said he spent yesterday speaking to the Israeli Prime Minister Benjamin Netanyahu and the Palestinian President Mahmoud Abbas – as well as other regional leaders – to try and push for a ceasefire.

“This is one of the most critical tests the region has faced in recent years,” Mr Ban said.

“Gaza is on a knife-edge. The deteriorating situation is leading to a downward spiral which could quickly get beyond anyone's control.”

Israel has said it will continue its offensive until rockets stop coming from Gaza. It said it hit more than 300 targets including Hamas positions, rocket-launchers and weapon storage sites – but Reuters reported that at least 50 of those killed on the Palestinian side have been civilians.

Palestinians and rescue workers stand near the rubble of a house which police said was destroyed in an Israeli air strike in Khan Younis in the southern Gaza Strip July 10, 2014 (Reuters)

“Hamas will pay a heavy price for firing toward Israeli citizens,” Prime Minister Benjamin Netanyahu said. “The operation will expand and continue until the fire toward our towns stops and quiet returns.”

Yuval Steinitz, Israel's intelligence minister, said he believed a “significant operation” involving ground troops was imminent, even though there would inevitably be heavy casualties on both sides.

He said: “Despite the fact it will be hard, complicated and costly, we will have to take over Gaza temporarily, for a few weeks, to cut off the strengthening of this terror army.”

The violence began building up three weeks ago after three Jewish students were abducted in the occupied West Bank. They were killed and their bodies were found last week. Then a Palestinian teenager was kidnapped and killed in Jerusalem.

Palestinian President Mahmoud Abbas, who is based in the Israeli-occupied West Bank, denounced the offensive on Wednesday.

“This war is not against Hamas or any faction but is against the Palestinian people,” he said.