(JTA) — The families of five American citizens killed in terror attacks in Israel are suing Facebook for $1 billion, accusing the social network of providing material support to Hamas for its incitement and violence.

Shurat HaDin-Israel Law Center, an advocacy organization based in Israel, filed the lawsuit Sunday night in Manhattan federal court. The suit alleges that Facebook is violating the U.S. Anti-Terrorism Act by assisting terror groups such as Hamas in “recruiting, radicalizing, and instructing terrorists, raising funds, creating fear and carrying out attacks.”

The lead plaintiffs have been identified as Stuart and Robbi Force, the parents of Taylor Force, a graduate student at Vanderbilt University and a U.S. Army veteran who was killed in March in a stabbing attack in Tel Aviv. Force had been on a school trip to Israel to study the tech industry.

The other plaintiffs are the relatives of dual Israel and U.S. citizens, including the parents of Naftali Fraenkel, 16, who was kidnapped from a West Bank bus stop and murdered along with two other Israeli teens in June 2014; the parents of Chaya Zissel Braun, 3 months, who was killed in a car-ramming attack in Jerusalem in October 2014; the son of Richard Lakin, 76, killed in a stabbing attack on a bus in the Armon Hanatziv neighborhood of eastern Jerusalem; and Menachem Mendel Rivkin, who was seriously wounded in a January stabbing attack in Jerusalem.

“Facebook has knowingly provided material support and resources to Hamas in the form of Facebook’s online social media network platform and communication services,” the plaintiffs alleged in a statement issued to the media. “Hamas has used and relied on Facebook’s online social network platform and communications services as among its most important tools to facilitate and carry out its terrorist activity.”

Facebook did not comment on the lawsuit when asked by several news outlets.