A group of U.S. citizens filed a federal lawsuit Wednesday charging that the Hamas-led massacre in Israel on Oct. 7, which killed 1,200 people and injured thousands more, was “masterminded and funded by the Islamic Republic of Iran.”

Among the 67 plaintiffs are people who were injured or taken hostage, as well as family members of those who were murdered.

“Iran bears direct responsibility for the October 7 Attacks,” according to the lawsuit, filed in U.S. District Court for the District of Columbia. “Indeed, that point is essentially undisputed. The Iranian regime has openly flaunted its motive for aiding the horrors.”

While it’s not clear what role Iran played in the attacks, a former U.S. intelligence and military officer said in October that the sophisticated tactics Hamas used to attack Israel indicated Iran most likely played a significant role in the multipronged assault.

In what appears to be the first attempt to hold it legally accountable for the bloody surprise attack that sparked the current war in Gaza, the plaintiffs contend that Iran, the “sworn enemy of Israel and the United States,” used Hamas to sabotage the ongoing diplomatic attempts to normalize relations between Israel and Saudi Arabia.

“As potential Israeli normalization with Saudi Arabia progressed, Iran prepared to reset the regional balance, including by attempting to unite Arab states around the Palestinian cause,” says the lawsuit, brought by the law firm Quinn, Emanuel, Urquhart and Sullivan LLP.

Iran’s Mission to the United Nations did not immediately respond to a request for comment.

“We expect to prove our case by several means, including affidavits from our clients as well as reports from experts on Iran and terror financing,” attorney Alex Spiro said in a statement to NBC News.

According to a State Department report, “Country Reports on Terrorism 2021,” “Hamas has received funding, weapons, and training from Iran and raises funds in Persian Gulf countries.”

From April to June 2023, Iranian leaders met with leaders of Hamas, Palestinian Islamic Jihad, or PIJ, and other affiliated militant groups in Syria and Iran “to encourage further acts of terrorism against Israel,” according to the lawsuit.

By August, commanders of the Quds Force — one of five branches of Iran’s Islamic Revolutionary Guard Corps, specializing in unconventional warfare and military intelligence — were meeting twice a week in a “Beirut war room” with “Hamas, PIJ, Hezbollah, and other Iranian-backed terror groups,” the lawsuit says, citing The Wall Street Journal and other published news reports.

Among those at the meetings was Iran’s foreign minister, Hossein Amirabdollahian, the lawsuit says.

Finally, on Oct. 2, the Iranians gave the “green light for Hamas, PIJ, and the other Iran-backed groups to launch the pre-planned attack against Israel, using Iranian intelligence, training, and military supplies,” it says.

Five days later, Hamas attacked southern Israel.

“That attack was an infamous, premeditated, and coordinated massacre in which terrorists murdered 1,200 people and injured nearly 5,000 more in the deadliest killing of Jews since the Holocaust,” the lawsuit says.

To “illustrate the depravity of Iran’s wrongdoing,” the plaintiffs recounted in the court papers some of the previously reported horrors that were visited on the Israeli victims on Oct. 7.

Among others, the lawsuit described how an American citizen named Yahonatan Siman-Tov, his wife, Tamar, and their three children choked to death after Hamas militants torched their home in the Nir Oz kibbutz. Their story was detailed in The Times of Israel.

“Their charred bodies were discovered holding onto one another in a final embrace, evocative of scenes from Nazi death camps,” the lawsuit says.

The lawsuit also recounts how Hamas-led terrorists “systematically murdered about 260 people” at the Nova music festival and how Hamas-led terrorists raped and killed many women.

To further buttress their case of violence and cruelty, the plaintiffs also included in the lawsuit photos of what appear to be dozens of men and women who were killed at the festival.

Among the images are graphic depictions of death, including images described as a “woman gagged and burned,” a “woman bound and burned” and a “beheaded baby.”

The plaintiffs, who, according to the lawsuit, are 60 U.S. citizens “and their family members who were victims of the October 7, 2023 attack in Southern Israel,” say Iran was directly responsible for what happened.

They are seeking unspecified punitive damages, damages from the U.S. Victims of State Sponsored Terrorism Fund, attorneys’ fees and “any and all other relief the Court deems just and proper,” the lawsuit says.

“Iran’s provision of funds, weapons, munitions, training, and intelligence to Hamas and PIJ provided those terror groups with material support and resources used to murder, torture, take hostage, and otherwise injure Plaintiffs, along with Israeli men, women, elderly, teenagers, children, toddlers, infants, and others,” it says.

And Iran, the plaintiffs said in the lawsuit, needs to be punished.

“In many places across the world, Iran’s actions have been met with silence,” the lawsuit says. “But Plaintiffs will not be silent. And the laws of the United States are not silent either.”

The plaintiffs “therefore bring this action to vindicate their rights and those of their loved ones—and to hold the government of Iran accountable,” the lawsuit says.