(CNN) -- An Alabama man described as a jihadist "rock star," two Minnesota women and a California man are among more than a dozen people now charged with aiding al Qaeda-linked rebels in Somalia.
The Justice Department unsealed a slew of indictments Thursday that accused 14 people of providing "money, personnel and services" to Al-Shabaab, the Islamist militant group battling Somalia's U.N.-backed transitional government. Most were in Minnesota, where the group has attempted to find recruits from among Somali immigrants.
FBI agents have arrested two women in Rochester, Minnesota, about 85 miles south of Minneapolis, on charges of raising money for the insurgents, the Justice Department announced. The rest named in Thursday's indictments are believed to be in Somalia, fighting with the rebels.
"While our investigations are ongoing around the country, these arrests and charges should serve as an unmistakable warning to others considering joining or supporting terrorist groups like Al-Shabaab: If you choose this route you can expect to find yourself in a U.S. jail cell or a casualty on the battlefield in Somalia," Attorney General Eric Holder told reporters Thursday.
Two men -- Omar Shafik Hammami, 26, a former resident of Daphne, Alabama, and Jehad Serwan Mostafa, 28, a former resident of San Diego, California -- have been charged in separate cases of providing material support to Al-Shabaab. Both are U.S. citizens, and are thought to be fighting alongside the rebels in Somalia, U.S. officials said.
Hammami in particular has become a "rock star" among jihadists, with rap-style videos that bridge American and Somali culture, said Frank Cilluffo, an analyst with the Homeland Security Policy Institute in Washington.
In one such video, Hammami declares, "Mortar by mortar, shell by shell, only going to stop when I send them to hell." In another, he boasts that he and his comrades are waiting for the enemy "away from our families, away from the cities, away from ice, candy bars."
"This isn't just someone reciting dusty old texts," Cilluffo said. "This is someone Americans see glimmers of themselves in."
Hammami was raised a Baptist in Alabama, but converted to Islam as a young man. His father, Shafik Hammami, said in a written statement, "What we know of the current situation is what everyone is learning from the same news reports, nothing more."
"Omar is my son and I love him dearly, just as a father should," he said. "However, I do not, in any way, condone his current philosophy nor his actions."
Holder said Hammami is now believed to be a ranking Al-Shabaab member who has "operational responsibilities."
Another indictment in Minnesota charged 10 men with leaving the country to join Al-Shabaab. Seven had faced previous related charges.
Abdikadir Ali Abdi, 19; Abdisalan Hussein Ali, 21; Cabdulaahi Ahmed Faarax, 33; Farah Mohamed Beledi, 26; and Abdiweli Yassin Isse, 26, are charged with conspiring to provide and providing material support to Al-Shabaab and conspiring to kill, maim and injure people abroad.
Faarax and Isse had been charged previously in a criminal complaint, and Abdi, Ali and Faarax are U.S. citizens, the Justice Department said.
Meanwhile, Ahmed Ali Omar, 27; Khalid Mohamud Abshir, 27; Zakaria Maruf, 31; Mohamed Abdullahi Hassan, 22; and Mustafa Ali Salat, 20, are charged with conspiracies to provide material support to terrorists and foreign terrorist organizations; conspiracy to kill, kidnap, maim and injure persons abroad; possessing and discharging a firearm during a crime of violence; and solicitation to commit a crime of violence. All five have been previously charged.
A separate indictment charged Amina Farah Ali, 33, and Hawo Mohamed Hassan, 63, on Thursday. The Rochester women, both of whom are naturalized citizens, were charged with providing material support to terrorists by raising money for the rebels among Somali immigrants in Minnesota, other states and Canada, Holder said.
"In some cases, these funds were raised under the false pretense that they would be used to aid the poor and the needy," Holder said.
The attorney general emphasized that innocent Muslims have been the victims of attacks by Al-Shabaab, al Qaeda, the Taliban, and other terror groups and pointed out that American Muslims have been vital in helping battle "this emerging threat" in the United States.
"These individuals have consistently -- and correctly -- expressed deep concern about the recruitment of their youth by terrorist groups," he said. "Many members of the community have taken proactive steps to stop the recruitment of their youth by terrorist groups. Just recently, a group of prominent American Muslims joined together in a video to repudiate the tactics employed by radicalized militants to recruit young Muslims via the internet."
The announcement comes a day after federal prosecutors in Chicago, Illinois, charged a U.S. citizen with trying to provide material support to two terrorist organizations -- al Qaeda and Al-Shabaab -- and with another charge related to weapons of mass destruction, according to a criminal complaint. Shaker Masri, 26, a U.S. citizen who lives in Chicago, was arrested Tuesday after he allegedly tried to violate a law that prohibits U.S. nationals "from using, threatening, attempting or conspiring to use a weapon of mass destruction outside the United States," the complaint said.
Minnesota is home to the country's largest population of Somali residents, according to the Minneapolis Foundation, a philanthropic community organization. Most of those Somalis came to the United States as refugees, the foundation says.
The 2000 Census showed that 13 percent of Minnesota's foreign-born residents were from Africa, a higher percentage than any other state in the country. According to the Minneapolis Foundation, there were 5,000 Minnesota residents in 1990 who had been born in Africa. Ten years later, that number had grown to more than 34,000.
CNN's Jeanne Meserve and Susan Candiotti contributed to this report.