Authorities are charging 14 men with providing support to the Somali terrorist group al-Shabab.
Most the men are U.S. citizens from Minnesota, California, and Alabama. Some are operating in the U.S., but most of the suspects are currently in Somalia fighting for the terrorists.
Attorney Gen. Eric Holder called the charges a disturbing tend.
"We are seeing an increasing number of individuals, including U.S. citizens, who have become captivated by extremist ideology and have taken steps to carry out terrorist objectives," he said.
"If you choose this route you can expect to find yourself in a U.S. jail cell or a casualty on the battlefield in Somalia," he added.
The charges are the latest in a string of cases involving Somalia-Americans giving support to al-Shabaab.
Terrorism expert Daveed Gartenstein-Ross of the Foundation for the Defense of Democracies told CBN News that these latest charges reflect an ongoing investigation much deeper than just three states.
Gartenstein-Ross appeared on the August 6 edition of CBN News' Morning program to talk more about the al-Shabab arrests. Click play for his comments.
"The largest federal terrorism investigation since 9/11 is currently on going and relates specifically to the Shabab support network for which we've had for more people going over to Somalia to liaise with the terrorist group and to aid their militant activities, or else to under take training that you've had for any other region of thew world," Gartenstein-Ross said.
In July, al-Shabab killed 76 people during a bombing in Uganda, their first international attack. The group also recently pledged its allegiance to Osama Bin Laden.