A mass funeral is held at the Tal as-Sultan cemetery in Rafah, southern Gaza, December 26, 2023 [Abed Zagout/Anadolu Agency]

Ramallah, February 1 (RHC)-- Palestinian authorities have demanded an international investigation after a mass grave was found in Gaza with the decomposing bodies of Palestinian detainees who were blindfolded and handcuffed.

At least 30 bodies were found in “black plastic bags” near the Hamad school in northern Gaza, with Palestinian officials accusing Israeli soldiers of killing the civilians “execution-style.”

The Palestinian Ministry of Foreign Affairs called for an international investigation on Wednesday into what it described as Israeli “massacres,” demanding that a team visit Gaza “to find out the truth and dimensions of the genocide to which our people are exposed.”

Witnesses told Al Jazeera that the deceased were blindfolded, tortured and killed before being placed in the bags.  “As we were cleaning, we came across a pile of rubble inside the schoolyard.  We were shocked to find out that the dozens of dead bodies were buried under this pile,” one witness told  Al Jazeera.

“The moment we opened the black plastic bags, we found the bodies, already decomposed.  They were blindfolded, legs and hands tied,” the witness added.  “The plastic cuffs were used on their hands and legs and cloths straps around their eyes and heads.”

Hamas said human rights organisations should “document” the mass grave.  “This heinous crime and others committed by the neo-Nazis against our Palestinian people will remain a curse that haunts them, and the day will come when they will be held accountable for their brutality and crimes that exceed the most horrific violations known to humanity in our modern era,” the Palestinian armed group said in a statement on Telegram.

Al Jazeera’s Tareq Abu Azzoum, reporting from Rafah in southern Gaza, said the “condition of these bodies ranges from severely decomposed to mere skeletal remains … making it hard to identify them.”  “But people still come to the site, searching for closure in this place of tragedy,” he added.

Palestinian human rights lawyer Diana Buttu told Al Jazeera on Thursday that this incident was “precisely why Israel was taken to the ICJ.“   Buttu added that the discovery of the mass grave was “clearly a war crime” and urged that it must be investigated.

The International Court of Justice has ordered Israel to take “all measures within its power” to avoid Palestinian casualties and acts that could amount to “genocide”.

The Foreign Ministry said the discovery of the mass grave was evidence of the forms of “genocide committed by the occupation forces against our people in the Gaza Strip without accountability or oversight”.

Palestinian detainees are routinely abused by Israeli forces in the enclave, subjected to weeks of imprisonment in unknown locations, beatings and verbal abuse.  Last month, a United Nations human rights official called for an end to Israel’s mistreatment of Palestinian detainees and said he had met men who had been held for weeks and were beaten and blindfolded.

“These are men who were detained by the Israeli security forces in unknown locations for between 30 to 55 days,” Ajith Sunghay, a UN human rights representative, told reporters by video link from Gaza, who met released detainees in the enclave.

“There are reports of men who are subsequently released, but only in diapers without any adequate clothing in this cold weather,” he said, adding that it was not clear why they were made to wear diapers but that “they were clearly visibly shocked and even shaken when I met them.”

Several videos shared by the Israeli army since the war began show hundreds of Palestinian men stripped to their underwear, sitting outdoors in the cold, sometimes blindfolded.  In a few videos, women and children were also seen.

Much of the densely populated Gaza Strip has been destroyed after four months of intense Israeli bombardments and ground offensive.  Gaza’s health authorities have said at least 26,900 Palestinians have been killed since the war began on October 7, following Hamas attacks in Israel that killed at least 1,139 people.