FBI agents have arrested six people in Minnesota and California as part of what they say is a terrorism investigation. The FBI has provided no details so far. The news comes after a 23-year-old Ohio man was arraigned last week for allegedly traveling to Syria to aid the al-Qaeda-linked al-Nusra Front. Prosecutors say Abdirahman Sheik Mohamud boasted of his skills to a government informant and planned to attack a military facility or prison within the United States. Meanwhile, Australian and British police say they have arrested a number of teenagers, including a 14-year-old boy, over an alleged plot to attack a war memorial ceremony in Australia.