MINNEAPOLIS — Two men who cooperated with authorities investigating a Minnesota conspiracy to join the Islamic State group in Syria were rewarded with light sentences Monday, but a third who didn’t help prosecutors got a 10-year sentence from a federal judge.

U.S. District Judge Michael Davis sentenced Abdullahi Mohamed Yusuf, 20, to 21 months already served in jail. Abdirizak Warsame, 21, didn’t fare as well, but his sentence of 2 1/2 years in prison was two years less than prosecutors sought. While all three pleaded guilty, Zacharia Abdurahman, 21, got 10 years in prison because he didn’t cooperate with the government and refused to testify against other members of what Davis called a “terrorist cell.”

Davis asked Abdurahman why he didn’t.

“As a man, I made a decision not to do that to my former friends. Your honor, I’m a man of principle. … Our religion teaches you not to harm another brother,” he replied, sniffing and wiping away tears as he stood before the court.

But Abdurahman also apologized to his family and community. He admitted that he was a committed supporter of the Islamic State and its violent jihadist ideology, though he said he abandoned it after his arrest. He agreed with Davis that he had been a terrorist. The judge’s sentence actually was five years less than prosecutors sought; Davis cited work by Abdurahman’s parents in a campaign against terror recruiting in Minnesota.

All three must also serve 20 years on supervised release.

In all, nine men pleaded guilty or were convicted of providing material support to a foreign terrorist organization. Three due for sentencing Tuesday pleaded guilty but did not cooperate. Three more due for sentencing Wednesday went to trial, where each was also convicted of conspiracy to commit murder outside the U.S. That charge carries a possible life sentence, though prosecutors are seeking sentences of 30 or 40 years.

Davis, who has handled all of Minnesota’s terror conspiracy cases, had the six defendants who pleaded guilty evaluated by a German expert on deradicalization and is taking those findings into consideration.

U.S. Attorney Andy Luger appeared in court to praise Yusuf and Warsame for cooperating.

The sentencings cap a long case that shined a light on terrorism recruitment in Minnesota, the state with the largest concentration of Somali immigrants in the U.S. The FBI has said about a dozen people have left Minnesota to join militant groups in Syria in recent years. Before that, more than 22 men were recruited to al-Shabab in Somalia since 2007.

Prosecutors said this conspiracy began in spring 2014, when a group of friends began inspiring and recruiting each other to join the Islamic State group. Some of their friends made it to Syria, but the nine didn’t.

At the day’s first hearing, Davis said it didn’t make sense to send Yusuf to prison, where no deradicalization programs are available.

“I hope I’m not wrong,” the judge said.

“I will not let you down, your honor,” Yusuf promised.

Earlier, Yusuf said he was “not the same naive 17-year-old” who was drawn into the conspiracy.

“ISIL’s ideology is flawed,” Yusuf said. “There is nothing Islamic about their so-called state.”

But the judge said he didn’t buy Warsame’s claims that he’s no longer a radical, suggesting he cooperated only because he could have faced 15 years in prison. Davis characterized Warsame’s contention that he had abandoned his jihadist ideology as merely “another chess move” by a skilled player.

“The problem I have with you is everything has seemed so smooth,” the judge said. He went on to add, “Extremist ideology based on religion doesn’t disappear overnight, and you can’t convince me otherwise. And that’s what you’re trying to do.”