Six Somali-American men who planned to travel to Syria to fight with the Islamic State of Iraq and the Levant (ISIL) group have been arrested on charges of conspiring to support an armed group.

The case was the latest in a series in recent months concerning Americans who have been accused of, or stopped from, travelling to the Middle East to join armed groups.

"They are all from Minnesota and are all part of the same conspiracy," federal prosecutor Andrew Luger told a news conference, saying the arrests were the result of a 10-month investigation by a joint task force.

The men, all friends or acquaintances in what authorities described as a "peer-to-peer" recruitment effort, had attempted to travel to Syria over the past year, with the help of an acquaintance who had made it to the war-ravaged nation and was actively recruiting volunteers in Minnesota.

Four of the men were arrested on Sunday in Minneapolis, while two were arrested in San Diego, where they attempted to acquire forged passports and then cross into Mexico to travel to Syria, according to the Justice Department.

"They were not confused young men, they were not easily influenced. These are focused men who were intent on joining a terrorist organisation by any means possible," Luger said.

The defendants were identified as Mohamed Abdihamid Farah, Adnan Abdihamid Farah, Abdurahman Yasin Daud, Zacharia Yusuf Abdurahman, Hanad Mustafe Musse and Guled Ali Omar.

Minneapolis, with its large Somali immigrant community, is a focal point for investigations on Americans seeking to join armed groups.

Several men between age 18 and 24 from immigrant families in Minnesota have succeeded in leaving the US and joining forces with ISIL and other groups.

Source: AFP