The Israeli military has said it has encircled the Jabalia refugee camp as the UN warns Gaza is on the brink of a 'hellish' situation. ITV News' Senior International Correspondent John Irvine reports
Israel has told residents to evacuate as forces pounded targets in crowded southern Gaza.
Israel military says it hit hundreds of Hamas targets and has destroyed about 500 tunnel shafts in Gaza.
The death toll in Gaza has now surpassed 15,800, the Hamas-run health ministry said, with 70% reported to be women and children.
Ceasefire talks have collapsed after Israel pulled its negotiators from Qatar, blaming Hamas for not fulfilling 'its part in the agreement'.
The Israeli Defence Forces (IDF) says its troops are now in the heart of Khan Younis, where people have been taking refuge in recent weeks.
As the Israeli military begins its ground offensive and continues it airstrike raid over the south of the territory, civilians are left with nowhere to go.
The commander of the IDF Southern Command, Major General Yaron Finkelman, described it as “the most intense day since the beginning of the ground operation - in terms of terrorists killed, the number of firefights, and the use of firepower from the land and air.”
Accounts from Khan Younis and Deir Al Balah further north describe intensive Israeli strikes, with many casualties being taken to the Al-Aqsa Martyrs Hospital, according to CNN.
An estimated 1.8 million people in Gaza are thought to be internally displaced, with the UN stating that "nowhere is safe" and "there is nowhere to go".
In a statement, Humanitarian Coordinator for the Occupied Palestinian Territory, Lynn Hastings, said over 700 Palestinians have reportedly been killed since the resumption of hostilities bringing the death toll to over 15,800.
She said: "The conditions required to deliver aid to the people of Gaza do not exist.
"If possible, an even more hellish scenario is about to unfold, one in which humanitarian operations may not be able to respond.
"What we see today are shelters with no capacity, a health system on its knees, a lack of clean drinking water, no proper sanitation and poor nutrition for people already mentally and physically exhausted: a textbook formula for epidemics and a public health disaster."
Rishi Sunak told Israeli Prime Minister Benjamin Netanyahu that more humanitarian aid is required in Gaza during a call on Tuesday, Downing Street said.
In a call between the two leaders on Tuesday, Mr Sunak said “more humanitarian aid had to be allowed to enter Gaza, where civilians were in desperate need”.
A Downing Street readout of the call said the Prime Minister “reiterated offers of practical UK support to facilitate deliveries of life-saving aid”.
Meanwhile, Defence Secretary Grant Shapps told MPs he will “move heaven and earth” to rescue hostages held by Hamas.
Gaza's Jabalia refugee camp is surrounded by troops, Israeli military says
While the operation is increasingly targeting the south of Gaza, the IDF has continued the campaign in the north.
On Tuesday, troops "completed the encirclement" of the Jabalia refugee camp in the north of the territory.
The camp, Gaza's largest, has been hit by renewed Israeli strikes in recent days following the end of the temporary ceasefire.
The IDF claim it found Hamas weapons and launchers had been located “in civilian compounds”.
UNICEF spokesman: 'Most intense suffering witnessed in 20 years'
After 20 years of working with UNICEF, spokesman James Elder says the situation in Gaza is one of "horrendous suffering" and of an "intensity" that he had never seen before.
Speaking to ITV News, he said: "In my 20 years of being in various places, and horrendous suffering people are enduring because of climate crises or because of horrendous conflicts.
"I don't think I've ever seen the intensity, in that every time I turned around, every single person, and don't use phrases like that lightly has a story of heartache."
'Everyone has lost a family member, a child with shrapnel and burns and a lost eye quite likely has also had their father killed,' James Elder told ITV News
Mr Elder added: "To see that level of suffering and hear this idea of a safe zone - or we won't commit the same horrors to the north, as to the south, was something I don't think I've experienced.
"It is mind boggling and totally unsettling for me how seemingly people in positions of power are able to turn away and close their eyes at the thousands and thousands of children killed and acquiesce that the killing is resumed."
Hamas hostage families meet with Netanyahu
The families of hostages held by Hamas in Gaza met Israeli prime minister Benjamin Netanyahu after demanding a sit-down with him.
They have been campaigning to meet Netanyahu and his Cabinet since a temporary ceasefire deal between Israel and Hamas that saw the release of 105 hostages expired.
'Each day that passes by, they are dying slowly': Parents of kidnapped soldier Itay Chen say they need to get hostages out 'whatever the price'
Parent of kidnapped soldier Itay Chen, Rubi Chen brought an hourglass to the meeting to illustrate that time is running out for his son.
He said: "We have no time. Each day that passes by, they are dying slowly each day. We need to get them out immediately, whatever the price might be."
The daughter of an Israeli woman released by Hamas militants has claimed her mother was "handcuffed" and "abused" during her time in captivity.
"There were rumours that the conditions were okay, that they were given food. They didn't receive food, they (Hamas) didn't give them water," said Shir Siegel during a Health Committee session at the Knesset in Jerusalem.
Shir’s mother, Aviva Siegel, was released by Hamas, but her father, Keith Siegel, remained in captivity - leading her to ask the committee why it was more important to "topple Hamas" than bring her father home.
Families claim Mr Netanyahu and other leaders have dodged their requests to meet for days.
It's reported that an estimated 135 hostages remain in Hamas captivity.
The families say they went to hear from Mr Netanyahu that he has their relatives’ fate in mind as Israel moves ahead in its conflict against Hamas.
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