(CNN) Families of 850 victims who died on 9/11 and 1,500 people injured that day are suing the Saudi government, accusing it of providing material and financial assistance to al Qaeda for years leading up to the worst terrorist attack on US soil.
It's one of largest 9/11-related lawsuits to be filed since Congress passed the Justice Against Sponsors of Terrorism Act over a presidential veto in September.
The act allows American citizens to bring lawsuits against states or countries accused of sponsoring terrorist attacks in the United States.
The complaint, filed Monday in federal court in Manhattan, alleges that the Saudi government, through its ministries and officials and a vast network of charities linked to the government, provided financial, practical and material support to al Qaeda.
"9/11 could not have happened without Saudi Arabia's support for al Qaeda," Jim Kreindler, attorney and co-chairman of the plaintiffs' committee, told CNN.
CNN has reached out to representatives for the kingdom of Saudi Arabia but hasn't received a response. Saudi Arabia has denied any role in the September 11 attacks and has never been formally implicated, but 15 of the 19 hijackers that carried them out were of Saudi descent.
The complaint cites parts of FBI and CIA reports, including the "28 pages," a declassified document released in July that found that some of the 9/11 hijackers were in contact with and received support from individuals likely connected to the Saudi government.
An earlier suit that is seeking class-action status represents the families of 1,400 victims who perished in the attacks. It has been the subject of an ongoing court battle since 2004 -- before passage of the Justice Against Sponsors of Terrorism Act -- and was held up at times in part because it named Saudi Arabia as a defendant
The original suit was amended Friday to consolidate with insurance companies seeking reimbursement for property damages, and those injured seeking damages.
Together, these two suits represent the majority of the victims in the terror attacks suing the kingdom. Nearly 3,000 people were killed that day.
"We intend, just like we have for over the last 13 years, to move forward to seek justice on behalf of all the families, and accountability on behalf of all the people in this country," attorney Jerry Goldman of the law firm Anderson Kill, who brought the original suit and is on the plaintiff's committee, told CNN.
A federal magistrate judge in New York has scheduled a conference Thursday with plaintiffs' attorneys and a representative from Saudi Arabia, according to attorneys for the plaintiffs.
Kreindler said he hopes to gain justice for his clients. "The suit is a suit for compensation, but most importantly there are thousands and thousands of 9/11 victims who want to hold Saudi Arabia accountable," he said.