More than 30 Harvard University student organizations are holding Israel "entirely responsible" for Hamas' mass slaughter --- sparking outraged condemnation and calls by a congresswoman for the Ivy League school to denounce the "abhorrent and heinous" support of "evil and terrorism."

In a letter titled "Joint Statement by Harvard Palestine Solidarity Groups on the Situation in Palestine," 31 student organizations --- including the Ivy League's affiliate of Amnesty International --- condemned Israel, even as its residents are kidnapped and more than 700 have been killed by the terrorist organization.

The groups claim Hamas' attack "did not happen in a vacuum," and the Israeli government has forced Palestinians to live in an "open-air prison for over two decades," according to the letter obtained by The Post

"We, the undersigned student organizations, hold the Israeli regime entirely responsible for all unfolding violence," the letter reads.

"The apartheid regime is the only one to blame," the groups claim.

“Israeli violence has structured every aspect of Palestinian existence for 75 years,” they continue.

“From systematized land seizures to routine airstrikes, arbitrary detentions, to military checkpoints, and enforced family separations to targeted killings, Palestinians have been forced to live in a state of death, both slow and sudden.”

“Today, the Palestinian ordeal enters into uncharted territory,” the groups wrote. “The coming days will require a firm stand against retaliation.

“We call on the Harvard community to take action to stop the ongoing annihilation of Palestinians.”

The Post has reached out to Harvard University for comment.

The letter was signed by groups including the African American Resistance Organization, Amnesty International, the Harvard Islamic Society and Harvard Jews for Liberation.

It sparked almost immediate condemnation, including from Rep. Elise Stefanik (R-NY), who graduated from Harvard in 2006.

“It is abhorrent and heinous that Harvard student groups are blaming Israel for Hamas' barbaric terrorist attacks that have killed over 700 Israelis,” tweeted the New York rep, a senior member of the House Armed Services Committee.

"Any voice that excuses the slaughter of innocent women and children has chosen the side of evil and terrorism.

"I am calling on the leadership of @Harvard to immediately publicly condemn these vile anti-Semitic statements."

Princeton professor Robert George also tweeted, "31 --- yes, 31 --- Harvard organizations have declared that the murders, r*pes, kidnappings, and other atrocities committed by Hamas against innocent people are in no way the fault of Hamas, but are rather entirely the fault of ... Israel.

"Something is deeply, deeply wrong in academia."

Political scientist Ian Bremmer, meanwhile, said he "can't imagine who would want to identify with such a group.

"Harvard parents---talk to your educated kids about this," he tweeted.

Aviva Klompas, a former speechwriter for the Israeli government, also took aim at the organizations for their support of the terrorist group.

"Israelis --- young and old --- were slaughtered in their homes. Entire families were butchered in cold blood," she wrote of the violence in Israel.

"In one home, a terrorist shot the parents dead, took a child's cellphone and livestreamed the horrors on the child's Facebook account. Elsewhere, dozens of young people were massacred at a music festival.

"Grandmothers were snatched from their homes and taken hostage. They took mothers carrying babies," she continued.

“Hamas is currently holding over 100 hostages, most of whom are civilians. Some are babies and children.

“Hamas acted with a savagery that can only be described as evil,” Klompas wrote. “But these students are so steeped in hate for Israel, that they are cheering on terrorists and denouncing the victims.”

Harvard's Palestine Solidarity Committee has previously come under fire for hosting anti-Israel events like a “Boycott Israel Trek,” and have claimed responsibility for getting the school newspaper, the Harvard Crimson, to support the controversial Boycott, Divest, Sanctions movement.