In this June 6, 2019, file photo, a US military Chinook helicopter lands in a field outside the governor's palace during a visit by the commander of US and NATO forces in Afghanistan.
CNN  — 

Family members of US service members who were killed or wounded in Afghanistan sued a number of prominent contractors on Friday that worked to rebuild the country post-invasion, accusing them of funneling millions of dollars in payments to the Taliban for protection that funded the group’s attacks on American troops in the region.

The suit, filed in Washington, DC, federal court, said the funds from the development and private security firms were part of a “common practice by certain corrupt contractors” that sought to save money on security by paying off the Taliban.

The firms allegedly used a network of subcontractors and private security groups to transfer cash to Taliban agents, and in some cases dole out salaries to certain Taliban “guards” between 2006 and 2014, while the group was allying with al Qaeda and waging a violent campaign against US forces and their allies, according to the lawsuit.

“Defendants decided that buying off the terrorists was the most efficient way to operate their businesses while managing their own security risks – even though doing so jeopardized other American lives,” the lawsuit says.

“Those protection payments aided and abetted terrorism by directly funding an al-Qaeda-backed Taliban insurgency that killed and injured thousands of Americans,” the suit added.

The allegations in the lawsuit are based on what lawyers for the service members’ families describe as describe as confidential witnesses, as well as internal company documents, declassified intelligence, congressional testimony and reports, and press accounts.

In public statements for more than a decade, US officials have opposed the practice of making payments to warlords and other corrupt groups, citing rules and regulations in place at the Department of Defense. In 2009, then-Secretary of State Hillary Clinton told lawmakers that the “protection money” was “one of the major sources of funding for the Taliban.”

CNN has reached out to the companies named in the suit, including MTN Group, a telecommunications firm accused of making payments to the Taliban while also allegedly deactivating their cellular network at night at the Taliban’s request.

MTN did not respond to a request for comment.

Another group of named defendants – DAI Global, the Louis Berger Group Inc. and Black & Veatch Special Projects Corp. – were some of the top contractors for the US Agency for International Development in Afghanistan, taking in more than $1 billion of the agency’s funding over a period of more than 10 years, according to the lawsuit.

In a statement, a spokesman for Black & Veatch would not comment on the pending litigation but said the company was following the directives of the US government agencies that it worked for.

“During our work in Afghanistan, we provided support to our client, United States Agency for International Development (USAID) and followed the directives of the US government agencies that we served,” said Patrick MacElroy, the company’s senior director of external communication. “We are proud of our record in successfully completing a number of projects in Afghanistan that helped more than double the amount of reliable power available to the country’s hospitals, schools, businesses and homes under its contract with USAID.”

DAI Global and the Louis Berger Group did not respond to requests for comment. Spokespeople for G4S Risk Management and for the parent company of the Centerra Group, two security firms named in the suit, had no comment.

The plaintiffs, who are 385 Americans, including dozens of veterans and members of Gold Star families, are accusing the companies of violating the Anti-Terrorism Act and are seeking damages.

“This case is about obtaining justice for my husband’s death and the lives of so many others who were killed and injured by the terrorists in Afghanistan,” August Cabrera, the widow of Lt. Col. David E. Cabrera, who was killed in a suicide bombing in Kabul, Afghanistan, in 2011, said in a statement.