Authorities in Minnesota say arrests have been made in connection with their terrorism investigation into youth who have traveled or tried to travel to Syria.

A spokesman for the U.S. Attorney's Office says the arrests were made Sunday in Minneapolis and San Diego but there is no threat to public safety. Spokesman Ben Petok did not elaborate on the number of people arrested.

The U.S. Attorney's Office and the FBI planned a news conference Monday to announce details. The announcement will include details of a "joint terrorism task force operation."

The FBI in Minneapolis has been investigating young people who have traveled or tried to travel to Syria to take up arms with militants.