BRUSSELS/LONDON - Israeli attacks in central Gaza killed scores of Palestinians, many of them civilians, amid a special forces operation to free four hostages held there, a death toll that has caused international outrage.

At least 274 Palestinians were killed and 698 wounded in Israeli strikes on the Nuseirat refugee camp in central Gaza, Gaza’s health ministry said on Sunday. The Israeli military said its forces had come under heavy fire during the daytime operation.

The EU’s top diplomat, Josep Borrell, called Saturday’s events a “massacre”, while the UN’s aid chief described in graphic detail scenes of “shredded bodies on the ground”.

“Nuseirat refugee camp is the epicentre of the seismic trauma that civilians in Gaza continue to suffer,” Martin Griffiths said in a post on X, calling for a ceasefire and the release of all hostages.

The bodies of 109 Palestinians, including 23 children and 11 women, were taken to nearby al-Aqsa Martyrs hospital in Deir al-Balah, which also treated more than 100 wounded, a spokesperson, Khalil Degran, told AP.

He also said more than 100 people killed in Israeli attacks had been taken to al-Awda hospital. That figure was also given by the Hamas media office, but could not be verified.

Fierce bombing and shelling in central Gaza continued on Sunday, killing six people, medics said, while tanks moved further into the centre of Rafah, Gaza’s southernmost city and its main gateway to the outside world.

The Israeli military spokesperson Rear Adm Daniel Hagari confirmed on Saturday that dozens of Palestinians had been killed in the raid. He knew that “under 100” casualties had been reported, but could not say how many were civilians, he told a briefing.

The rescue in Nuseirat, a built-up refugee camp dating to the 1948 Arab-Israeli conflict, was Israel’s largest such operation of the war, freeing Noa Argamani, 25, Almog Meir Jan, 21, Andrey Kozlov, 27, and Shlomi Ziv, 40. All four were healthy and were reunited with their families on Saturday after medical tests.

Scores of hostages are believed to be held in densely populated areas or inside Hamas’ labyrinth of tunnels, making such operations extremely complex and risky. A similar raid in February rescued two hostages and killed 74 Palestinians.

While Israelis celebrated their return, Palestinians in Gaza mourned the many dead or watched over injured loved ones in the overcrowded al-Aqsa Martyrs hospital.

Bombing of Nuseirat’s busy market area began soon after the raid started at around 11am (9am BST), turning the neighbourhood into “smoke and flames”, Muhannad Thabet, a 35-year-old resident, told AFP.

“People were screaming – young and old, women and men,” he said. “Everyone wanted to flee the place, but the bombing was intense and anyone who moved was at risk of being killed due to the heavy bombardment and gunfire.”

At least one wave of heavy airstrikes was launched to secure the passage of the three men, who had been held together. Argamani was rescued alone, from a separate location.

The special forces team extracting the male hostages was confronted by militants, Israel’s Channel 12 television reported, and when a rescue vehicle got stuck, called in backup from Israel’s air force and other troops in the area. They escaped under heavy bombardment, the report said. Eyewitnesses also reported tank and drone fire.

But beyond Israel, the hostages’ joyful reunions with their families were overshadowed by the horror at the number of people killed during the operation.

Borrell, in a post on X, condemned “in the strongest terms … reports from Gaza of another massacre of civilians”. He called for a ceasefire and the release of all remaining hostages. “The bloodbath must end immediately,” he said.

Israel’s foreign minister, Israel Katz, lashed out at critics of the operation in a post on X: “Only Israel’s enemies complained about the casualties of Hamas terrorists and their accomplices.”

As the war drags on into its ninth month, Netanyahu has come under increasing international pressure to agree a ceasefire deal and domestic pressure to secure the return of all Israelis still held in Gaza.

The rescue operation may give the prime minister temporary relief at home. After the news broke, his political rival Benny Gantz, a security cabinet member, delayed a speech planned for Saturday evening. He had been widely expected to announce his departure from government, having given Netanyahu an ultimatum to form a long-term plan for Gaza. The prime minister urged him not to step down on Saturday, but in a statement, Gantz’s office said the minister would speak on Sunday evening instead.

Hostages’ families have been quick to repeat their demands for a ceasefire deal to release their loved ones, saying in a statement on Saturday evening that the military could not bring back all those still held captive.

“The hostages don’t have time. We can’t free everyone in operations and we must go for a deal that will save lives,” said Ayala Metzger, the daughter-in-law of the hostage Yoram Metzger, 80, who this week was announced to have died in captivity.

Israeli forces have now freed seven hostages, but the majority of those who are now home were handed over under a temporary ceasefire deal last November. There are still 120 held in Gaza, at least a third of whom are presumed to have died.

On Sunday, Hamas’s armed wing posted a video to its Telegram channel showing what appeared to be three unidentifiable corpses with censor bars over their faces, claiming that the bodies belonged to three hostages, including a US citizen, who were killed during the Israeli rescue operation.

Internationally, the death toll in Gaza may isolate Netanyahu further and give additional weight to calls for a halt to fighting.

American intelligence was reportedly involved in supporting the Israeli mission. The US president, Joe Biden, welcomed the return of the four hostages, but also said efforts to reach a deal to halt the war and secure the return of everyone held in Gaza would continue.

While the US remains Israel’s largest supplier of weapons and most important international ally, Biden has personally pushed hard for an agreement and apparently been frustrated by resistance in the Israeli government. He suggested in a recent interview that Netanyahu may be prolonging the war to protect his personal political interests.

Hamas has still not officially responded to the latest deal on the table proposed by Israel and outlined by Biden last week.