As the Israeli army advances on Gaza City, thousands of families remain in the city’s crowded tent camps.

Sky News analysis of satellite imagery taken on Monday 15 September shows tent camps stretching across the western half of the city.

A close-up view shows one camp spilling out on to the city’s beaches.

The Israel Defence Forces (IDF) launched its ground assault overnight on Tuesday 16 September, in what the military said was a “new phase” in its offensive.

“Gaza is burning,” defence minister Israel Katz posted on X as the operation began. “IDF soldiers are fighting bravely to create the conditions for the release of the hostages and the defeat of Hamas.”

UK Foreign Secretary Yvette Cooper described the offensive as “utterly reckless and appalling”, adding that it “will only bring more bloodshed, kill more innocent civilians & endanger the remaining hostages”.

Footage verified by Sky News shows Israeli tanks entering the Gaza Strip from the north overnight on Tuesday.

Israeli soldiers later filmed themselves in an area just north of Gaza City.

Satellite imagery taken a day earlier shows that while some tent camps in the area have been abandoned in the past few days, many others have not.

The IDF advance comes after an intense week of airstrikes targeting buildings in Gaza City. Sky News has verified dozens of videos showing strikes on buildings across the city.

Several of these strikes destroyed entire tower blocks, such as this strike on Al Ghafari Tower.

At least 50 people were killed across the Gaza Strip on Tuesday, health officials said, most of them in Gaza City.

The IDF said it estimated 40% of people in Gaza City had fled south, while Hamas said that only 190,000 out of 1.3 million residents had left (15%).

An evacuation order for the entire city was first issued on 9 September, with a map on 13 September instructing Palestinians to flee to what Israel has designated a “humanitarian area” along a stretch of sandy coastline known as Al Mawasi.

Satellite imagery from Sunday 14 September shows that the area is already crowded with tents.

Last week, the UN’s Gaza humanitarian country team said that “neither the size nor scale of services provided is fit to support those already there, let alone new arrivals”.

Those fleeing south face a journey of at least 15km (9.3 miles), much of it through Israeli-designated combat zones. Local health officials said at least one vehicle travelling south from Gaza City had been hit by an Israeli strike.

Among those staying put on Tuesday was Um Mohammad, who lives in the Sabra neighbourhood of Gaza City.

“It is like escaping from death towards death, so we are not leaving,” she said.

The IDF says the next stage of the operation will involve both air and ground forces, and that the number of soldiers involved will increase over the coming days.

Additional reporting by Sam Doak, OSINT producer.

The Data and Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We gather, analyse and visualise data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open source information. Through multimedia storytelling we aim to better explain the world while also showing how our journalism is done.

Tyler Robinson has been charged with the murder of right-wing US influencer Charlie Kirk.

The 22-year-old, from Washington, Utah, was charged with aggravated murder, weapon, and obstruction of justice offences ahead of a court appearance later on Tuesday.

Prosecutors said they would seek the death penalty and that Robinson’s DNA was found on the trigger of the alleged murder weapon.

A note was also found under his keyboard which said: “I had the opportunity to take out Charlie Kirk and I’m going to take it,” according to a charging document from prosecutors.

It is also alleged that the suspect ordered his roommate to delete “incriminating texts” about the killing and to stay silent if questioned by police.

When his roommate texted to ask if he was the “one who did it”, Robinson replied: “I am, I’m sorry,” prosecutors allege.

Robinson is said to have written in another text: “I had enough of his hatred. Some hate can’t be negotiated out.”

He also allegedly wrote he had been planning the shooting for just over a week.

Kirk, 31, was killed at one of his rallies at Utah Valley University last Wednesday.

The political activist, a close ally of US President Donald Trump, died after being shot in the neck with a bullet.

County attorney Jeff Gray said “aggravating factors” in the killing included that the “defendant is believed to have targeted Charlie Kirk based on his political expression and did so knowing children were present and would witness the homicide”.

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The obstruction of justice charges relate to allegations that Robinson disposed of the weapon used in the killing, along with clothing he is said to have worn at the time.

Robinson has been held without bail since his arrest.

Investigators have spoken to Robinson’s relatives and have carried out a search at his family home, 240 miles (385km) southwest of where the shooting took place.

Mr Gray said Robinson had accused Kirk of “spreading hate” during a conversation with his father. He also allegedly described the university as a “stupid venue” for the influencer to hold an event.

After the shooting, the county attorney said the suspect confessed to his parents after they confronted him, telling them he shot Kirk because “there is too much evil in the guy”.

Robinson’s mother told police that her son had become more political and had “started to lean more to the left” in the past year or so, Mr Gray said.

He added that the 22-year-old had become more “pro-gay and trans-rights oriented”, according to his parents.

His mother said he had started to date his roommate, who was “transitioning genders”, prompting “discussions” with his father who had very different political views.

Robinson allegedly wrote in another message to his roommate that “since Trump got into office [my father] has been pretty diehard Maga”.

The FBI director has shouted at Democratic senators during a hearing, taking questions on the assassination of Charlie Kirk, Jeffrey Epstein and the firing of agents.

Kash Patel was testifying before a Senate Judiciary Committee for the first oversight hearing of his tenure as director of the US federal law enforcement bureau.

During the hearing on Tuesday, Mr Patel defended the FBI’s handling of the investigation into the killing of Mr Kirk, as well as his social media post saying that a suspect had been arrested, before that person was ultimately released.

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“Could I have been more careful in my verbiage and included ‘a’ subject instead of ‘the’ subject? Sure,” he said of the post.

Democratic senator Cory Booker opened his questioning by accusing Patel of lying about firing FBI agents out of retribution for political investigations.

Five FBI agents and top-level executives were known to have been summarily fired last month, according to the Associated Press.

Mr Booker said that the director “pushed out senior FBI agents with decades of knowledge and experience”, and added: “You’ve shifted the agency’s priorities primarily to pursuing Donald Trump’s immigration enforcement agenda.

“I believe you have made our country weaker and less safe.”

Mr Patel responded that “you don’t get to say that America is not safer under this leadership”, and said that Mr Booker’s “rant of false information does not bring this country together”, prompting the Democrat to raise his voice.

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The two then shouted at each other before committee chair and Republican senator Chuck Grassley banged his gavel to interrupt them.

“I’ve watched him talk over us, and you’ve never once criticised him for us,” Mr Booker said to the chair as he got up to leave the room. “He has been really disrespectful to senator after senator.”

Mr Patel also clashed with Democratic Senator Adam Schiff, who questioned the FBI and Trump administration’s handling of questions relating to the deceased paedophile financier Epstein.

The director accused him of “the biggest fraud to ever sit in the United States Senate” as they shouted at each other, and said “you are a political buffoon, at best”.

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Mr Patel, a former lawyer who has been accused of spreading conspiracy theories, was controversially nominated to be the FBI director by US President Donald Trump last year.

He was narrowly confirmed by the Senate in a 51-49 vote in February. Two Republicans voted against his nomination.