The former head of the Central Intelligence Agency and the National Security Agency says the hysteria over a 2015 U.S. military exercise in Central Texas, known as Operation Jade Helm 15, was caused or fed by Russians working to use information warfare.

The exercise became big news when conspiracy theorists began spreading rumors that it was part of a government plot to lay the groundwork for martial law and mass internment.

KUT reported at the time:

On Monday, dozens of people filled the Bastrop County Commissioners Court to voice concerns about the military exercises. [Lt. Col. Mark] Lastoria took a number of questions from people who suspect Jade Helm is something nefarious. Bastrop County resident Daniel DuCloux has some reservations about the training program.

"I think historically, it's much more common for governments to be tyrannical and infringe on other's rights,” DuCloux said. “So when you see a large military build-up like this, I think it's our duty as citizens to question what's going on and to find answers. I mean, if we don't, then who will?"

Air Force Gen. Michael Hayden, who served as NSA director and CIA chief under Presidents Bill Clinton, George W. Bush and — briefly — Barack Obama, told MSNBC’s Morning Joe on Wednesday that Russians sought to “use dominance in the information space to directly attack the will of an adversary population and win that way.”

Former NSA and CIA Director Michael Hayden speaking on MSNBC's "Morning Joe."

Hayden says they used such attacks within Russia and when Russia annexed Crimea in 2014.

“They took their game to North America in 2015,” he told Morning Joe.

“There was an exercise in Texas called Jade Helm 15 that Russian bots and the American alt-right media convinced most — many — Texans was an Obama plan to round up political dissidents, and it got so much traction that the governor of Texas had to call out the National Guard to observe the federal exercise to keep the population calm.”

In fact, Abbott called up the Texas State Guard, which is a separate branch of the Texas Military Forces. (More about the State Guard here.)

I've ordered the Texas State Guard to monitor Jade Helm 15 to safeguard Texans' constitutional rights, private property & civil liberties — Greg Abbott (@GregAbbott_TX) April 28, 2015

“At that point, I’m figuring the Russians are saying, 'We can go big-time,’” Hayden said. “And at that point, I think they made the decision, 'We’re going to play in the electoral process.’”

The Texas Democratic Party, which highlighted Hayden’s comments on Thursday, criticized the governor’s reaction.

“Republican Gov. Greg Abbott was a Russian pawn and a useful idiot for Russian efforts to instill fear and distrust in our American institutions,” said Deputy Executive Director Manny Garcia.

Abbott’s office had no comment on Hayden’s remarks or Texas Democrats’ accusations when contacted Thursday.

Operation Jade Helm 15 was held from July 15, 2015, to Sept. 15, 2015, in Texas and several other southwestern states, and was mostly unnoticed by most people in the area.