In Washington, U.S. Homeland Security Secretary Janet Napolitano said the report was consistent with a growth in cases of Americans who have become radicalized to commit such acts of violence. She confirmed that there have been cases of Somali-Americans who have been recruited to fight in Somalia, but declined to comment on whether that particular trend was accelerating.

Somali Islamic insurgents — some of whom have links to al-Qaida — have been recruiting young Somali men in America and other countries amid fears that insurgents could use the men to attack foreign targets.

The first known American suicide bomber in Somalia, Shirwa Ahmed from Minneapolis, blew himself up in October 2008 in the northern breakaway republic of Somaliland as part of a series of coordinated explosions that killed 21 people.