MINNEAPOLIS — U.S. law enforcement is investigating a new phenomenon of women from the American heartland joining Islamic State as President Obama vows to cut off the militants’ recruiting at home.

At least three Somali families in the Minneapolis-St. Paul area have female relatives who have gone missing in the past six weeks and may have tried to join “Islamic State,” said community leader Abdirizak Bihi. He said that while the reasons for their disappearance were unclear, he had told the families to contact police.

In a separate case, a 19-year-old American Somali woman from St. Paul snuck away from her parents on Aug. 25, saying she was going to a bridal shower. Instead, she flew to Turkey and joined IS in Syria.

Home to the biggest Somali community in the United States, the Twin Cities area of Minnesota has been plagued by terrorist recruiting since the Somali group al-Shabaab began enlisting in America around 2007.

This year, law enforcement officials say they learned of 15-20 men with connections to the Minnesota Somali community fighting for extremist groups in Syria. They included Douglas McAuthur McCain, a convert to Islam, who was killed in battle this summer.

The St. Paul woman is the first case of an area female joining IS that has been made public, although her family have asked for her name to be kept private because it fears retaliation from Islamists.

Greg Boosalis, FBI division counsel in Minneapolis, said law enforcement was investigating the possible recruitment in the area by Islamist extremists of other females, as well as males, but refused to comment on specific cases.

“We are looking into the possibility of additional men and women travelers,” he said.

Somali leaders and sources close to police worry that the reports of female would-be jihadis from the region could mark a new trend.

The St. Paul woman is highly likely to have been recruited by IS through Islamist sympathizers in the United States, rather than joining the group on her own, they said. At least one other woman is suspected of helping her leave the United States.

Another U.S. teenager, nurse’s aide Shannon Conley, 19, from Colorado, pleaded guilty this week to trying to travel to the Middle East to enroll in IS. She was arrested at Denver International Airport in April with a one-way ticket and had been recruited online by a male militant in Syria.

The Somali woman from St. Paul who traveled to Syria attended a mosque near the eastern bank of the Mississippi River, which had previously attracted suspected extremists. In June, the mosque banned an Egyptian-American man it said was spreading radical ideology.

The woman told a relative after leaving the United States that she wanted to help children in IS-controlled territory in Syria.

“The nature of the recruitment of these crazy organizations is how they use the element of surprise. Now they have surprised us again by going for the girls,” said Bihi, speaking about the St. Paul woman who he said was targeted by recruiters.

Bihi’s teenaged nephew was killed in Somalia in 2009 after being persuaded to join al-Shabaab while in Minnesota.