CNN  — 

Four hostages have been rescued in an Israeli operation that took weeks of planning – but killed scores of Palestinians in Gaza and left behind a trail of devastation.

At least 274 Palestinians were killed in the operation and hundreds injured, Gazan authorities said, who do not distinguish between civilian and military casualties.

While there has been euphoria for the families of the four rescued – Noa Argamani, Almog Meir Jan, Andrey Kozlov, and Shlomi Ziv, eight months after they were kidnapped from the Nova music festival on October 7 - celebrations could be brief.

Israel’s Prime Minister Benjamin Netanyahu remains under intense pressure, with his goal of destroying Hamas and rescuing the remaining hostages still distant. He has refused to sign up to the latest peace plan, presented by US President Joe Biden last week, and the toll among Palestinians continues to rise.

Here’s what we know about Saturday’s operation.

What happened in the raid?

Unusually, the Israel Defense Forces (IDF) opted for a daytime raid on the Nuseirat camp in central Gaza on Saturday - saying that it allowed them a greater element of surprise.

As part of their preparations, the military built models of the apartments the hostages were held in after receiving intelligence regarding their location.

“Israeli forces have been preparing for this rescue mission for weeks. They underwent intensive training,” Israel Defense Forces (IDF) Rear Admiral Daniel Hagari told a press briefing.

Hagari said Israeli forces had to enter civilian areas to reach hostages as this was where Hamas had embedded itself.

Some of the special forces were disguised as displaced Palestinians and as members of Hamas’s military wing, according a witness as well as reporting from CNN analyst Barak Ravid, citing eyewitnesses in the refugee camp. CNN has?reached out to the IDF for comment.

Without the cover of darkness, the IDF ran a greater risk of failing to get in and out of Gaza safely. One officer was shot and killed during the operation, according to Israeli police.

Israeli armored vehicles drive through Deir al-Balah, Gaza, on June 8.

Hagari said the IDF had received intelligence on the location of the hostages beforehand, noting that hostages in Gaza were frequently moved around and Argamani had previously been held elsewhere. Similar raids had been called off at the last minute “more than three or four times” due to unfavorable conditions, he added.

The first phase of Saturday’s operation saw the IDF target militant infrastructure with pre-planned strikes, Hagari said.

Hagari said that the IDF had come under intense fire, especially after withdrawing from the apartments, but did not provide evidence for his claims.

“While under fire, under fire inside the buildings, under fire on the way out from Gaza, our forces rescued our hostages,” he said.

Ravid, the CNN analyst, also reported there was a “robust firefight” after the hostages were rescued.

Why was the Palestinian toll so high?

The raid took place mid-morning, meaning the streets were teeming with people shopping at a nearby market.

The hostages were held in civilian buildings, according to the IDF, in the midst of the densely populated camp. Hagari said the hostages had been locked in two separate apartments in multi-story buildings about 200 meters (650 feet) apart, with Argamani held in a different building to the three men.

There were early indications of an ongoing mission when Israel announced ahead of the news on Saturday morning it was operating in Nuseirat, but it had launched a new offensive in the area midweek. Heavy bombardment was reported during the Israeli rescue mission.

There are varying reports on the number of Palestinians killed. The latest figures from Gazan authorities say 274 Palestinians were killed and 698 injured – which would mark one of the deadliest days in months for people living in Gaza.

The IDF has disputed those numbers, saying it estimated the number of casualties from the operation was “under 100.” CNN cannot independently verify either side’s figures.

But local residents described the attack as a “hell on earth,” with scenes of carnage following the strikes that led up to the rescue. Eyewitnesses have described civilians being struck down by airstrikes and shrapnel.

One local Palestinian?man named Abu Abdallah told a CNN stringer on the ground that people were struck in their homes at around 5am local time. “We tried to get ambulances, but no?one could enter as it was already a military zone,” he said.

Palestinians look at the aftermath of Israeli attacks in Nuseirat refugee camp, Gaza, on Saturday, June 8.

“Dogs were eating people’s remains, we pulled out six martyrs, all torn up children and women, we risked our lives to get them to the hospital. The soldiers told us to go back but we had to continue,” he added.

Another local resident, Nidal Abdo, said he was shopping at?Nuseirat?market before “a crazy bombardment started hitting everywhere.”

“[It was] something we never witnessed before, maybe 150 rockets fell in less than 10 minutes, while we were running away more fell?on?the market,” he said.

Footage from?Al-Aqsa Martyrs Hospital, in nearby Deir al-Balah, shows trucks and ambulances transferring injured people and bodies to the hospital. The hospital’s emergency room is overwhelmed. People can be seen in the footage waiting?on?the hospital floor.

Graphic video shows many Palestinians, including children, injured with blood on their faces and clothes. Footage from the hospital?also shows people screaming and crying, huddled over bodies covered in blankets.

What’s the reaction been?

Families of the hostages expressed their overwhelming joy at having their loved ones returned safely. Orit Meir, mother?of?Almog Meir Jan, said at a news conference Saturday that she was excited to hug her son again.

“I couldn’t stop hugging him,” she said. “Tomorrow is my birthday so I got my present.”

Argamani was reunited with her terminally ill mother, who suffers from Stage 4 cancer.

Almog Meir Jan, a rescued hostage, embraces his loved ones after the military said that Israeli forces have rescued four hostages alive.

Netanyahu - who met with the rescued hostages and their families at Sheba Hospital on Saturday - called the operation “heroic,” adding that the government would continue “to do everything we can” to recover all those being held in the enclave.

The operation was “a great light in the terrible?darkness,” Israeli opposition leader Yair Lapid said Saturday.

Avi Marciano, father of Corporal Noa Marciano, a 19-year-old hostage who died in captivity, said Netanyahu’s public celebrations over the hostage releases contrasted with how he reacted when the outcome was not as positive.

“I am truly happy from the bottom of my heart for the families that were fortunate and able to hug their loved ones. I’m also envious,” Haaretz quoted him as saying. “This emphasizes how bad our ending was. When the ending is bad, the prime minister doesn’t show up. He doesn’t call, either.”

Hamas meanwhile accused?Israel?of committing “a horrific massacre” on civilians in Nuseirat. The militant group said?Israel’s killing of scores of people as it mounted a hostage rescue operation was a “brutal crime, devoid of the values of civilization and humanity.”

Palestinian?leader?Mahmoud Abbas has called for an emergency session of the?UN?Security Council while several MIddle Eastern countries condemned the operation.

After the rescue mission, US national?security adviser?Jake Sullivan said an “enduring ceasefire” deal?between Israel and Hamas is “the only credible path forward.”

Sullivan acknowledged the civilian toll of Israel’s military operation Saturday while saying Hamas, which took the hostages during its deadly October 7 attacks on Israel, was putting Palestinians in harm’s way.

What does it mean for the war?

Hostage rescues are rare. This is only the third such successful operation of the conflict.

Saturday’s operation shows they are still possible and may encourage further efforts from the Israeli military, given a major goal of Israel’s Gaza offensive is to rescue the remaining hostages.

However some have pointed to a ceasefire deal as a much more effective way of freeing the hostages. More than 100 hostages were freed under a temporary truce last year, while Israel has rescued seven hostages by military means.

A protest for the release of hostages in Tel Aviv on Jun 8.

Hagai Levine, of the health team at the Hostages and Missing Families Forum, said operations such as the one seen on Saturday were “not a way we can bring 120 hostages back home.

“We must, all of us together, the world, follow President Biden speech and go with the deal that will enable all of them, dead or alive, come back home with a ceasefire.”

Instead, Levine called for a ceasefire deal that would “enable all of [the hostages], dead or alive” to be brought back home.

There are warnings that the IDF’s deadly operation on Saturday may have further set back a potential ceasefire agreement.

An Egyptian official told CNN that Israel’s operation will have a “negative effect” on negotiations to end the war in Gaza.

“[It] won’t be easy,” the Egyptian official, who is familiar with the talks, told CNN.

Egypt, along with Qatar, has been helping to coordinate negotiations between Israel and Hamas.

On Sunday, the US called for a vote on its UN Security Council resolution backing the proposal for a permanent ceasefire and release of the hostages in?Gaza.

“Israel has accepted this proposal and the Security Council has an opportunity to speak with one voice and call on Hamas to do the same,” Nate Evans, the spokesperson for the US Mission to the UN, said in a statement Sunday. “Doing so would help save lives and the suffering of civilians in?Gaza?as well as the hostages and their families,” he said.

Since November, intensive negotiations over a ceasefire and a deal to swap hostages for Palestinian prisoners have landed in a stalemate.

Israel last month pressed ahead with its ground operation in central Rafah despite?international condemnation?for its escalation in the southern Gaza city where some?1.3 million Palestinians?were taking shelter before Israel began its operation there.

CNN’s Teele Rebane, Hande Atay Alam, Michael Rios and Lauren Izso contributed to this report.