FBI spokeswoman Laura Eimiller says the defendants were arrested for plotting to bomb government facilities and public places. They include a man who served in the U.S. Air Force.
According to a federal complaint unsealed Monday during initial appearances, 34-year-old Sohiel Omar Kabir introduced two other California men to the radical Islamist doctrine of Anwar al-Awlaki, a deceased al-Qaida leader.
Kabir served in the Air Force from 2000 to 2001. Authorities say he went to Afghanistan and communicated with the other two - 23-year-old Ralph Deleon and 21-year-old Miguel Alejandro Santana Vidriales - so he could arrange for their travel to join him and meet with his contacts for terror organizations.
They later recruited 21-year-old Arifeen David Gojali.
The complaint says Deleon and Santana told an FBI source of their plans to engage in "violent jihad."