U.S. prosecutors unveiled criminal charges on Monday against two alleged leaders of a white supremacist gang, saying they used the Telegram social media site to solicit attacks on Black, Jewish, LGBTQ people and immigrants aiming to incite a race war.

The group, dubbed "The Terrorgram Collective," used the site to celebrate white supremacist attacks around the world and solicit racially motivated violence, prosecutors said in an indictment unsealed in federal court in Sacramento, California.

Dallas Humber, 34, of Elk Grove, California, and Matthew Allison, 37, of Boise, Idaho, each face 15 criminal counts, including soliciting hate crimes and conspiring to provide material support to terrorism. The two were in custody, officials said; it was not immediately clear if they had lawyers.