The House Homeland Security Committee says the US is failing to stop most people trying to go overseas to join terrorist groups, including the Islamic State.
In a report Tuesday, the committee says more than 250 Americans have joined or tried to join terrorist groups in Iraq and Syria. It said dozens have been able to successfully return to the United States.
The committee says the government lacks a comprehensive strategy to combat terrorists and people trying to travel abroad to join terrorist groups as a so-called foreign fighter.
Terrorist groups, including the Islamic State, are also becoming more sophisticated in their efforts to recruit US citizens and other Westerners to join the fight.