Promising both "true brotherhood" and "fun," several Somali men convinced fellow immigrants in Minneapolis to return to their East African homeland and take up arms with a terrorist group, according to federal charges unsealed Monday against eight individuals.

The charges are part of an unfolding federal investigation into the disappearance of as many as 20 young Somali men from Minneapolis over the last two years _ most of them U.S. citizens who federal authorities say are guilty of terrorism. Federal prosecutors say most of the men traveled to Somalia to join the terror group al-Shabab, which the U.S. State Department says has links to al-Qaeda.

Ralph S. Boelter, the special agent in charge of the FBI's Minneapolis field office, called the latest round of indictments a "tipping point" in the more than yearlong investigation. "We have reached momentum, and reached a point where we will have full resolution of this case," Boelter said at a news conference with Minnesota's U.S. Attorney, B. Todd Jones.

Fourteen people have been charged in the investigation. The eight charged Monday are accused of a mix of recruiting and raising funds for the trips, and of engaging in terrorist acts in civil war-torn Somalia. Indictments say some attended terrorist training camps where they received instruction in firing small arms and machine guns, military style tactics and indoctrination in "anti-Ethiopian, anti-American, anti-Israel, and anti-Western beliefs," according to a federal affidavit.

Two of those charged Monday helped raise money for the trips by approaching unknowing members of Minnesota's Somali community and soliciting funds by telling them it was to pay for trips for young Somali men to travel to Saudi Arabia and study the Koran, according to the affidavit.

Boelter and Jones said one reason they disclosed new details about the case was to reassure members of Minnesota's Somali community that the investigation is focused on a relatively small group of individuals. The larger community "has consistently expressed deep concern about this pattern of recruitment activity," Jones said.

Still, the federal officials declined to say whether any of the new indictments targeted alleged leaders or masterminds of the recruitment scheme. The investigation is ongoing, they said, and there could be more indictments and arrests. Federal officials declined to name a local mosque which court documents allege was a site for some recruiting and planning.

Of the 14 people indicted, four have pleaded guilty and are awaiting sentencing. Seven are not in custody and are believed to be outside the United States.