Six Minnesota men were charged with terrorism in a criminal complaint unsealed Monday, the latest Westerners accused of traveling, or attempting to travel, to Syria to join the Islamic State group.

The six, whom authorities described as friends who met secretly to plan their travels, are accused of conspiracy to provide material support and attempting to provide material support to a foreign terrorist organization. The complaint says the men planned to reach Syria by flying to nearby countries from Minneapolis, San Diego or New York City, and lied to federal investigators when they were stopped.

Charged are brothers Mohamed Abdihamid Farah, 21, and Adnan Abdihamid Farah, 19; Abdurahman Yasin Daud, 21; Zacharia Yusuf Abdurahman, 19; Hanad Mustafe Musse, 19; and Guled Ali Omar, 20. All are Somali-Americans, authorities said.

“These were focused men who were intent on joining a terrorist organization,” Minnesota U.S. Attorney Andy Luger said at a news conference Monday.

The six were arrested Sunday in Minneapolis and San Diego. They are the latest Minnesota residents to be charged in a monthslong investigation into the recruitment of Westerners by the Islamic State. Authorities said earlier that a handful of Minnesota residents have traveled to Syria to fight with militants in the past year, and at least one has died.

Three of those charged in the latest complaint — Mohamed Farah, Abdurahman and Musse — were stopped at a New York City airport in November along with 19-year-old Hamza Ahmed, but they were not charged until now.

Ahmed was indicted on charges of lying to the FBI during a terrorism investigation, conspiring to provide material support to the Islamic State, and attempting to provide material support. He has pleaded not guilty.

Despite being stopped already, Luger said, the other three continued to try to get to Syria “by any means possible.”

The complaint describes several interactions some of the men had with Abdi Nur, a Minnesotan charged previously with conspiracy to provide support to a terror organization. The complaint says Nur, “from his locale in Syria, recruits individuals and provides assistance to those who want to leave Minnesota to fight abroad.”

The complaint relies in part on material from a confidential informant who had himself conspired to join the Islamic State before he changed his mind and went to authorities. Some of the informant’s conversations with the six men were recorded.

The Minneapolis area is home to the largest concentration of Somali immigrants in the U.S. Since 2007, more than 22 young Somali men have also traveled from Minnesota to Somalia to join the militant group al-Shabab.

Omar’s older brother, Ahmed Ali Omar, was among those who joined al-Shabab, leaving Minnesota in December 2007, according to the complaint. Ahmed Omar remains a fugitive. The complaint also said when agents went to the younger Omar’s house after he was stopped in San Diego in November, another brother, Mohamed Ali Omar, threatened them.