The three Somali-American men, Guled Omar, 21, Abdirahman Daud and Mohamed Farah, both 22, were convicted Friday on multiple counts in Minnesota federal court.
All the three men, who could face life in prison, were not "wayward kids who just got caught up in a fantasy," US Attorney Andrew Luger said.
"They wanted to fight for a brutal terrorist organization, kill innocent people, and destroy their own families in the process," Luger said.
The men were also accused of conspiring and attempting to provide material support to ISIS.
Farah was also convicted of lying to a grand jury and FBI agents. Omar was found guilty of attempting to use $5,000 of student financial aid in the plan. Daud, however, was acquitted of a perjury charge.
Prosecutors used over two dozen witnesses, clandestine audio recordings and terror videos in the trial that went to the jury on Wednesday.
Farah's attorney, Murad Mohammad, said he and his client were critical of the verdict. Mohammad said Farah's actions did not amount to a conspiracy to murder anyone or provide material support to ISIS.
In addition to the three people, 10 more men were charged with planning to go abroad in order to join ISIS.
Three of them were convicted on Friday and six pleaded guilty to giving material support to ISIS. A tenth man is believed to be in Syria.
A study released last November shows that the overwhelming majority of terror suspects charged in the US for their alleged ties with ISIS are American citizens.
Of the 68 people who have been indicted because of alleged involvement in Daesh (ISIS / ISIL) terrorism, 55 or about 81 percent are US citizens, including 44 who were born in America, according to the study published by Center on National Security at Fordham University.
The ISIS terrorists, many of whom were initially trained by the CIA in Jordan in 2012 to destabilize the Syrian government, are engaged in crimes against humanity in the areas under their control.
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