text: At least six men were arrested in California and Minnesota by the FBI on Sunday after a joint terrorism task force investigation into youths who traveled or tried to travel to Syria to join ISIS. A spokesman for the US Attorney's Office said the arrests were made in Minneapolis and San Diego but there is no threat to public safety. Spokesman Ben Petok did not give details about the charges and said more information would be released on Monday. Scroll down for video . Arrests were made Sunday in Minnesota and California after an investigation into youths traveling to join ISIS in Iraq and Syria (file picture) Three men who were arrested in Minneapolis (above) were already known to authorities, according to reports . Cross country: A Somali mother said one son was arrested in Minneapolis and the other was arrested in San Diego (above) At least three men who were arrested in the Twin Cities were already known to authorities, according to KMSP. The three men were stopped from boarding a plane to Istanbul with Hamza Ahmed, 19, at JFK Airport after riding on a Greyhound bus with him from Minneapolis to New York in November. Ahmed was indicted for lying to the FBI during a terrorism investigation, conspiring to provide material support to the ISIS and attempting to provide material support in February. He has pleaded not guilty. No public charges were filed against his companions and little information was released about them. An FBI affidavit said they are all between the ages of 19 and 20 and live in the Twin Cities. A Somali woman said one of her sons was arrested at her house in Minneapolis around noon and the other was arrested in San Diego, according to MPR News. She said she didn't know why more than 12 FBI agents and police officers searched her house and confiscated a tablet. The FBI made at least six arrests in Minneapolis and San Diego following a joint terrorism task force operation . The US Attorney's Office and the FBI will hold a news conference Monday to announce details about the joint terrorism task force operation. An FBI spokesman in San Diego referred questions to a spokesman in Minneapolis, who said Sunday he could not comment. Authorities say a handful of Minnesota residents have traveled to Syria to fight with militants within the last year. At least one Minnesotan has died while fighting for the Islamic State. Since 2007, more than 22 young Somali men have also traveled from Minnesota to Somalia to join the terrorist group al-Shabab. Four Minnesotans have already been charged in connection with supporting terror groups in Syria, including ISIS.
target: Arrests made Sunday after investigation into youths traveling to join ISIS .
  Details are scarce but authorities said there is no threat to public safety .
  Three men arrested in the Twin Cities were already known to authorities .
  Reportedly rode bus to NYC with Hamza Ahmed and tried flying to Istanbul .
  19-year-old charged with lying to FBI and trying to provide support to ISIS .
  The US Attorney's Office and the FBI will hold a news conference Monday .