Two people who prosecutors say were motivated by white supremacist ideology were charged Monday with using the messaging app Telegram to encourage acts of violence against minorities, government officials and critical infrastructure in the United States.

The defendants, identified as Dallas Erin Humber and Matthew Robert Allison, face 15 federal counts in the Eastern District of California. It was not immediately clear whether either had an attorney, but both were due in court either late Monday or Tuesday.

Justice Department officials say the defendants used Telegram to transmit bomb-making materials, to distribute a list of potential targets for assassination — including a federal judge, a senator and a former U.S. attorney — and to celebrate perpetrators of prior acts of violence.

The pair are accused of leading a collective of channels on Telegram known as “Terrorgram” that prosecutors say promotes white supremacy and violence. Their exhortations to violence included statements such as “Take Action Now” and “Do your part,” according to an indictment unsealed Monday.

“I think it would be difficult to overstate, the danger and risks that that this group posed,” Assistant Attorney General Matthew Olsen, the Justice Department’s top national security official, said at a news conference.

(AP)