The Foreign Ministry condemned Israel's strike on a school, where displaced people were taking refuge in the southern Gaza Strip.
The mass graves discovered in largely destroyed Khan Younis, and the targeting of four schools in as many days are "concrete evidence” that Israel seeks to destroy the Palestinian people, it said in a statement.
The attacks also showed that the government of Israeli Prime Minister Benjamin Netanyahu wants to undermine cease-fire negotiations, it added.
Israeli officials will be held accountable for actions that disregard all values of humanity and international law, said the ministry.
Several victims were killed and dozens injured in the Israeli strike Tuesday, according to medics.
Last week, the Israeli army issued evacuation orders for residents of several areas in eastern Khan Younis.
Since the outbreak of the Gaza conflict, the Israeli army hit several Palestinian displacement centers in Gaza, killing dozens.
Flouting a U.N. Security Council resolution demanding an immediate cease-fire, Israel has faced international condemnation amid its continued brutal offensive on Gaza since an Oct. 7 attack by the Palestinian resistance group, Hamas.
More than 38,200 Palestinians have since been killed, mostly women and children, and over 88,000 injured, according to local health authorities.
Nine months into the Israeli war, vast tracts of Gaza lie in ruins amid a crippling blockade of food, clean water and medicine.
Israel is accused of genocide at the International Court of Justice, whose latest ruling ordered it to immediately halt its military operation in the southern city of Rafah, where more than 1 million Palestinians had sought refuge from the war before it was invaded on May 6.
