Three American citizens have been arrested on allegations they used cryptocurrency to fund what they believed would be weapons purchases for attacks on U.S. service members overseas.

The defendants collectively provided more than $2,000 that they believed would be used to buy drones and rocket-propelled grenades for the attacks, according to a criminal complaint filed Thursday.

The complaint alleges Bisaam Ghafoor, 21, of Leawood, Kansas; Elias Shamsaldeen, 21, of Porterville, California; and Bereen Dzayee, 25, of Lakeside, California, pledged allegiance to the Islamic State group and discussed wanting to leave the U.S. to fight for ISIS.

Each was charged with one count of conspiracy to provide material support or resources to a foreign terrorist organization. If convicted, each faces up to 20 years in federal prison, a lifetime term of supervised release, and a fine of up to $250,000.

"This administration has put terrorists, cartels, and gangs on notice," acting Attorney General Todd Blanche said Friday in a news release. "Today's arrest of three individuals who allegedly conspired to provide material support to ISIS makes clear our commitment to taking down terrorist networks — anywhere.

"Thanks to the vigilance of the FBI, their alleged scheme was dismantled and further acts of violence against U.S. service members were prevented."

The complaint alleges the money was sent to FBI-controlled sources and undercover employees rather than actual ISIS members.

According to the complaint, Ghafoor's name was written on the projectile of a rocket-propelled grenade purportedly intended for use in an attack on U.S. service members overseas.

The complaint also alleges Shamsaldeen provided money intended to purchase drones that would be used in the attacks.

As detailed in the complaint, Ghafoor said it would be "sick" if his name were written on a drone used in an attack on Americans.

Later, a confidential source sent him an image purportedly showing his name written on a rocket-propelled grenade.

Dzayee suggested that drone targets should include U.S. special forces. In other exchanges, Shamsaldeen expressed a desire to stab and injure a U.S. service member.

Ghafoor also said he had always wanted to kill a female soldier by beheading, and added, "I wish I could kill 300,000,000 Americans."

The Department of Justice said the three men were arrested Friday morning. It was not immediately clear whether all three had made initial court appearances.