Lawmakers clash over threat from American jihadists

“These individuals directly undermine our homeland security,” McCaul said. “They have been recruited inside the U.S., have left, and could potentially return – presenting a vast vulnerability in our counterterrorism efforts.”

Ranking member Bennie Thompson (D-Miss.) said homegrown extremists are a bigger concern. He suggested last month's attack that killed more than 60 people in Nairobi would repel rather than attract young Somali-Americans to al-Shabaab's cause and urged Republicans to increase funding for Homeland Security grants.

“It seems that the Boston Marathon bombing has turned all the conventional wisdom about violent extremism upside-down and confirmed that people do not need to travel abroad to learn violent and destructive behavior,” he said. “Violent extremism can be homegrown.”

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