Beit Lahia, Northern Gaza - The dead bodies of some 30 Palestinians have been found in a school in north Gaza after the Israeli military’s withdrawal, following weeks of heavy fighting which has laid waste to the area and cut off civilians from communication and aid.

The bodies were discovered in the Khalifa bin Zayed school in Beit Lahia in north Gaza – an area which had been besieged for weeks. Israeli forces also conducted mass arrests of Palestinians in the area.

According to footage aired by Al Jazeera on Wednesday, the bodies were found handcuffed and blindfolded in plastic bags which had been buried underneath piles of dirt and sand.

The discovery has raised suspicions that the individuals were subjected to summary executions by the Israeli army. It is not yet clear who the victims are.

Graphic footage of the bodies being unearthed from the sand by civilians has been shared on social media. In the video, plastic cable tags with Hebrew text can be seen tied around the bottom of the bags.

The Palestinian Prisoners Club, which monitors Palestinians imprisoned by Israel, said that the fact that the bodies were handcuffed and blindfolded indicated they had been arrested, then subjected to a field execution.

The Palestinian Ministry of Foreign Affairs has called for an international investigation into accusations that Israel has been executing prisoners in Gaza.

"According to testimonies of Palestinian citizens, more than 30 decomposing bodies of Palestinian martyrs were discovered buried in the northern Gaza Strip," the ministry said.

"They were killed while blindfolded and with their hands tied, as clear evidence that they were executed… in the most horrific forms."

"The ministry believes that the discovery of this mass grave in this brutal form reflects the scale of the tragedy to which Palestinian civilians are exposed, the mass massacres and executions of even detainees, in flagrant and gross violation of all relevant international norms and laws."

Under the Geneva Convention on the treatment of prisoners in war, prisoners must be humanely treated at all times. Article 13 states that any unlawful act by the detaining power which causes death or the serious injury of a prisoner in its custody is prohibited.

Since Israel began its offensive in Gaza, there have been increasing reports of executions, abuse, and arbitrary arrests by Israeli forces against Palestinian men, women, and children.

In December, reporters from Al Jazeera discovered around 15 decomposing bodies at a school near the Jabalia refugee camp in north Gaza which was being used as a shelter for displaced families.

Eyewitness and relatives of the victims said they were shot at point-blank range by Israeli soldiers.

Israel has repeatedly struck civilian buildings such as schools, hospitals, mosques, churches and universities during its four-month long aerial and ground assault on Gaza.

Aid convoys and medical workers have also been targeted with UN agencies and humanitarian organisations in recent weeks urging global powers to implement a ceasefire to allow the proper entry and distribution of aid to the devastated population.

Almost 27,000 Palestinians have been killed in the military campaign, which was sparked by Hamas’ unprecedented attack on Israel on October 7 which killed over 1,200 Israelis and saw the group take over 200 hostages.