Twice as many Americans as previously reported by law enforcement have traveled overseas to join an al-Qaida-linked organization, a congressional investigation found.

The findings, discussed in a congressional hearing on Wednesday, are an indication the Somalia-based terrorist group has an even deeper reach into the U.S.

More than 40 Americans have traveled to war-torn Somalia to join the terrorist group al-Shabab, an investigation by Republican staff on the House Homeland Security Committee found.

Al-Shabab, which initially focused on regional grievances, has expanded its focus to include targeting the West and recruiting Americans toward that cause.

Counterterrorism officials fear the terror group with ties to al-Qaida is a growing threat to the U.S. In at least one instance, the government said, al-Shabab received terror training from al-Qaida's offshoot in Yemen.
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