A rose is left at the 9/11 Memorial on September 11, 2014 in New York City. Photo: Eric Thayer/Getty Images

A lawsuit filed in Manhattan court last week accuses the government of Saudi Arabia of “knowingly providing material support and resources to the al Qaeda terror organization and facilitating the September 11th attacks.”

Families of about 800 9/11 victims and 1,500 first responders and other survivors are joining the suit, filed by aviation firm Kreindler & Kreindler. It is one of the first to take direct legal action against the Saudi government. The plaintiffs are seeking monetary damages, though the amount hasn’t been specified, reports NBC 4.

A total of 15 of the 19 hijackers were from Saudi Arabia, and Congress declassified 28 pages of the 9/11 Commission Report last year that outlined potential Saudi involvement in the deadly attack.

Last fall, Congress overrode President Obama’s veto of the Justice Against Sponsors of Terrorism Act. The law allows terror victims to sue foreign states for any alleged involvement in attacks, which paved the way for this and similar lawsuits. (Previously, citizens could only bring lawsuits against those countries officially designated by the U.S. as state sponsors of terror.) Obama opposed the law, saying it would open American citizens and corporations up to suits, but Congress, in a rare bipartisan showing, passed the law over the president’s objections.