About 20 men released from Israeli custody “have bruises and marks of blows on their bodies”, Marwan al-Hams, hospital director in the southern city of Rafah, said.

Hams said the freed Palestinians were admitted to Al-Najjar hospital upon their release.

The Israeli army rejected the claims, saying detainees are “treated in accordance with international law”.

“While detained, the suspects are given sufficient food and water and treated according to protocol,” the army said in a statement.

Israel’s mass arrest campaign sows fear in northern Gaza

Nayef Ali, 22, said he was detained in Gaza City’s eastern Zaitun suburb and later taken to an Israeli detention facility, and showed cuts on his wrists and other parts of his body.

“They [Israeli troops] tied our hands behind our backs for two days,” he said.

“We were not allowed to eat or drink, neither were we allowed to use the toilet,” he added.

“There were only beatings and beatings.”

Ali said the detainees were put in an area along the border with Israel where it was “freezing cold”.

“They threw cold water on us before transferring us to a prison, where it was again torture and beatings.”

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Four-year old American girl freed as Hamas and Israel release hostages under a 4-day truce

Four-year old American girl freed as Hamas and Israel release hostages under a 4-day truce

Khamis al-Bardini, 55, also alleged torture by Israeli soldiers, saying they poured “cold water on our heads through the night” along with “beatings during the day”.

In recent weeks, the army has faced international criticism after viral footage of detainees stripped down to their underwear and blindfolded with their hands tied behind the backs.

The army has said it was investigating the deaths of “terrorists in military detention centres” after Israeli media reported that several detainees had died in custody.

Meanwhile, Israeli Prime Minister Benjamin Netanyahu said on Sunday that the war was exacting a “very heavy price” as the toll of soldiers killed in fighting with Hamas mounted.

“This is a difficult morning, after a very difficult day of fighting in Gaza,” he said after the army announced 14 soldiers had been killed in the Palestinian territory since Friday.

“The war is exacting a very heavy price … but we have no choice but to keep fighting,” he added in a statement.

“We are continuing with full force until the end, until victory, until we achieve all of our goals: the destruction of Hamas, the return of our hostages and ensuring that Gaza will never again constitute a threat to the State of Israel.”

He added: “Let it be clear: This will be a long war … [until] Hamas is eliminated and we restore security in both the north and the south.”