The Palestinian Ministry of Foreign Affairs has called for the formation of an international investigation team to look into accusations that Israeli forces executed prisoners, Al Jazeera reports.

“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 in a statement. “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.”