Israel said its forces rescued on Saturday four hostages alive from a Gaza refugee camp where the Hamas-run government media office reported attacks left 210 Palestinians dead and hundreds wounded.

The Israeli military said the four, who were in "good medical condition", had been kidnapped from the Nova music festival during Hamas's October 7 attack that sparked war with Israel, now in its ninth month.

Noa Argamani, 26, Almog Meir Jan, 22, Andrey Kozlov, 27, and Shlomi Ziv, 41, had been rescued from two separate buildings "in the heart of Nuseirat" camp in a "complex daytime operation", the military said.

They are among seven captives freed alive by Israeli forces since Palestinian militants seized 251 people in their October attack on southern Israel.

There are now 116 hostages remaining in Gaza, including 41 the army says are dead.

Footage posted on social media showed beachgoers erupting into cheers in Tel Aviv when a lifeguard announced the four had been freed.

"We have had these hostages in our thoughts for every day for the better part of a year now -- to have even a few of them rescued against all odds, it means the world," 42-year-old Israeli Uriya Bekenstein told AFP.

In Gaza, the Hamas media office said "the number of victims from the Israeli occupation's massacre in the Nuseirat camp has risen to 210 martyrs and more than 400 wounded".

Israeli police said an officer was mortally wounded during the rescue operation.

It was carried out despite growing international pressure on Israel after a deadly strike on a UN-run school in Nuseirat where displaced Gazans were sheltering.

"We are determined to bring back home all the hostages," said military spokesman Rear Admiral Daniel Hagari.

Hamas's Qatar-based leader Ismail Haniyeh vowed to keep fighting.

"Our people will not surrender, and the resistance will continue to defend our rights," Haniyeh said in a statement.

- Ceasefire 'essential' -

Israeli Prime Minister Benjamin Netanyahu has faced regular street protests demanding a deal to bring the captives home, with demonstrators rallying again on Saturday in Tel Aviv.

"Noa (Argamani) is home! We want all of them!" read one banner at the protest.

On Saturday Netanyahu pledged to return the rest of the captives, saying the latest raids "have proven that Israel does not surrender to terrorism".

His office also released a video of him speaking with Argamani on a mobile telephone.

She said she was "very excited" to return home, adding: "I haven't spoken Hebrew in such a long time."

US President Joe Biden welcomed the rescue operation, saying: "We won't stop working until all the hostages are home and a ceasefire is reached. That's essential to happen."

He was speaking in Paris alongside French President Emmanuel Macron, who said: "We rejoice at the release of the four Israeli hostages."

Near Nuseirat on Saturday, an AFP photographer saw scores of Palestinians fleeing the Bureij camp on foot, fearing further Israeli strikes.

The operation came days after the Israeli strike on the Nuseirat school run by the UN agency for Palestinian refugees, UNRWA, which a Gaza hospital said had killed 37 people and the military said targeted "terrorists".

UNRWA condemned Israel for striking a facility it said had been housing 6,000 displaced people.

Israel accuses Hamas and its allies in Gaza of using civilian infrastructure, including UN-run facilities, as operational centres -- charges the militants deny.

The war has brought widespread devastation to Gaza, with one in 20 people dead or wounded, according to the Hamas-run territory's health ministry. Most of Gaza's 2.4 million inhabitants are displaced.

Gaza City resident Yussef al-Dalu said his neighbour's house had been reduced to rubble in an overnight air strike. Emergency services reported five dead.

"Only defenceless civilians live in this house who are not part of any resistance (group)," Dalu told AFP.

- 'Challenges remain' -

The Hamas attack that triggered the war resulted in the deaths of 1,194 people, mostly civilians, according to an AFP tally based on Israeli official figures.

Israel's retaliatory military offensive has killed at least 36,801 people in Gaza, also mostly civilians, according to the Hamas-run territory's health ministry.

Israel faces growing diplomatic isolation, with international court cases accusing it of war crimes and several European countries recognising a Palestinian state.

Thousands of people marched through central London to the British parliament on Saturday calling for a ceasefire, and demonstrators gathered outside the White House to protest Washington's support for Israel amid Gaza's deadliest-ever war.

Netanyahu also faces pressure from within his government.

The premier in a social media post on Saturday called on war cabinet minister Benny Gantz to "not leave the emergency government" after threats last month to quit unless Netanyahu approves a post-war plan for Gaza by June 8.

Gantz had earlier cancelled a news conference scheduled for Saturday where Israeli media had speculated he would announce his resignation.

But in brief remarks on Israeli television, Gantz on Saturday evening urged his colleagues in government to "look responsibly" into "how we can continue from here".

"Alongside the justified joy over this achievement, it should not be forgotten that all the challenges Israel is facing... have remained as they were," he said.

Efforts to mediate the first ceasefire in the conflict since a week-long pause in November appear to have stalled after Biden offered the latest plan for a multi-phase truce and hostage release.

Major sticking points include Hamas insisting on a permanent truce and full Israeli withdrawal from all parts of Gaza -- demands Israel has rejected.

US Secretary of State Antony Blinken is set to visit Israel and key regional partners Egypt, Jordan and Qatar from Monday.