The three men were among hundreds detained by Israeli forces over alleged links with the Palestinian resistance group "Hamas".
Photos captured by news agencies show wounded Palestinians who were detained by the Israeli army during attacks in northern Gaza. The men released via the Karm Abu Salem crossing now await treatment for their injuries at Al-Najjar hospital in Rafah.
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, told AFP.
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 told AFP in a statement.
Nayef Ali, 22, said he was detained in Gaza City's eastern Zaitun suburb and later taken to an Israeli detention facility; he showed cuts on his wrists and other parts of his body.
"They (Israeli troops) tied our hands behind our backs for two days," Ali 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 [Israeli soldiers] threw cold water on us before transferring us to a prison, where it was again torture and beatings."
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".
Brahim , a Gaza resident from Beit Lahia, told DPA news agency that he endured torture during his four weeks of detention. Furthermore, he detailed how he and a dozen others were led from their neighbourhood to Israel, hands tied and blindfolded, and forced to keep their heads low inside a military lorry.
"We didn't know whether we would be killed or what the army would do to us," Brahim recalled, recounting instances where he and fellow prisoners were repeatedly forced to undress.
The Israeli officials, who interrogated Brahim in Arabic, asked him hundreds of questions about Hamas, its leaders, activities, and the tunnels in the Gaza Strip, he continued.
He detailed being subjected to various forms of physical and psychological torture and how he was sometimes accused of lying and was often beaten.
After several weeks, the Israeli army brought Brahim back to the Gaza Strip. On the return journey, he said soldiers beat him and threatened to kill him soon.
Similarly, a 39-year-old woman named Hind from Gaza City also said she was abused during her captivity in Israel. "Men and women from the Israeli army beat me all over my body," Hind told DPA.
During her three-week detention, she and other detainees struggled without access to basic necessities like food, water, and toilets.
In recent weeks, the army has faced international criticism after footage of detainees stripped down to their underwear and blindfolded with their hands tied behind their backs went viral.
The army said it was investigating the deaths of "terrorists in military detention centres" after Israeli media reported that several detainees had died in custody.
Earlier on Sunday, Hamas reiterated its plea to the International Committee of the Red Cross to intervene and disclose the status of numerous Palestinians from the Gaza Strip "who were captured and detained by the Zionist occupation forces under ambiguous circumstances," the group said in a statement.
Moreover, the movement urged human rights organizations to record the accounts of the released Palestinians with the intent "to present these testimonies to the relevant international courts and to hold the leaders of the Zionist entity accountable for their fascist behavior against our people and innocent civilians," added the statement.
On Saturday, the Geneva-based Euro-Med Human Rights Monitor urged UN bodies to immediately form “an international delegation to visit Israeli prisons and detention camps, where more than 8,000 Palestinian detainees are currently held.”
Euro-Med added that “evidence mounts of widespread violations, of mass arrests, forced disappearances, torture, ill-treatment, and even killings” of Palestinian prisoners in Israeli jails.
"After their arrest, detainees have been subjected to systematic abuse such as being stripped of their clothes, handcuffed, blindfolded, severely beaten, harassed, sexually assaulted, deprived of sleep, food, water, and basic hygiene and degraded in front of cameras,” the European human rights organization said in a letter.
Euro-Med added that “the number of Palestinians detained in administrative detention… has reached an unprecedented level, while the fate and whereabouts of many of them remain unknown.”
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