MINNEAPOLIS  — A Minnesota man who joined al-Shabab in Somalia more than seven years ago and more recently went online to urge others to carry out violence on behalf of the Islamic State group has turned himself in to authorities in Africa, the U.S. State Department said Monday.

Mohamed Abdullahi Hassan surrendered to Somalia’s federal government on Nov. 6, the State Department said in an email to The Associated Press. It’s not immediately clear why his arrest wasn’t announced earlier.

State Department spokeswoman Pooja Jhunjhunwala said Hassan was in the custody of the Somali National Intelligence and Security Agency in Mogadishu. She said the U.S. Mission to Somalia is discussing the case with the Somali Federal Government, but the U.S. does not have an extradition agreement with Somalia.

“We do not have any further details on the discussions at this time,” Jhunjhunwala said.

The U.S. Attorney’s Office in Minnesota, which charged Hassan with multiple terrorism-related counts, had no comment. The FBI office in Minneapolis also declined to comment.

Hassan, who went by the nickname Miski when he was in Minneapolis, was just 17 and a high school senior when he left the U.S. to join al-Shabab in August 2008. Some in Minneapolis remember him as a quiet, soft-spoken kid. But in recent years, Hassan had become a vocal supporter of the Islamic State group, posting jihadist rhetoric online.

Tweeting under the name “Mujahid Miski,” Hassan urged his Twitter followers to carry out acts of violence in the U.S. — including beheadings. He also commended attacks elsewhere and used protests of police activity in Ferguson, Missouri, and Baltimore to try to recruit others to the jihadist cause.

Most notably, Hassan was among those urging an attack on a Prophet Muhammad cartoon contest in Garland, Texas, last May. Before the attacks, Hassan tweeted: “The brothers from the Charlie hebdo attack did their part. It’s time for brothers in the (hash)US to do their part.”

Rita Katz, director of SITE Intelligence Group, said Hassan had at least 33 Twitter accounts and used social media to help recruit a new class of jihadists, including some from Minnesota.

“One of his important activities was he was reaching out to people that he knew, people that were somehow connected to him, and recruiting them,” she said.

Katz said if the State Department’s announcement is true, it would make sense because al-Shabab has been attacking and killing those who supported the Islamic State group. “If he wants to save his life, he did the right thing,” she said.

She also added that while news of Hassan’s surrender is important, there are many others who are willing to take his place online.

Omar Jamal, head of the Somali Human Rights Commission, said he hopes Hassan will be brought to Minnesota to face justice “because he created havoc in his tweets. … he recruited tons of people through social media.”

In addition to his online messages, Hassan was directly tied to some Islamic State group recruits. According to court documents, Hassan became Facebook friends with another Minnesota man roughly two months before that man went to Syria to join the Islamic State group.