A former U.S. soldier has been arrested and charged with illegally using a weapon on behalf of an al Qaeda-affiliated group in Syria . Eric Harroun , 30 , of Phoenix was arrested Tuesday night by the FBI at a hotel near Washington Dulles International Airport in Virginia . A Justice Department official tells CNN that FBI agents questioned Harroun at the hotel , then took him into custody . Harroun appeared Thursday in federal court in Alexandria , Virginia , and was charged in connection with his alleged use of a rocket-propelled grenade in Syria . The law used to charge him states , `` Any national of the United States who , without lawful authority , uses or threatens , attempts , or conspires to use a weapon of mass destruction outside of the U.S. shall be imprisoned for any term of years or for life , or if death results , may be punished by death . '' Harroun served with the U.S. Army from 2000 to 2003 . He is not charged with targeting U.S. troops in Iraq . The organization he allegedly fought with , al-Nusra Front , is one of several aliases used by the al Qaeda in Iraq terrorist organization . The organization claims responsibility for nearly 600 terrorist attacks in Syria , the Justice Department said . An FBI affidavit says Harroun crossed into Syria in January 2013 and fought against Syrian President Bashar al-Assad 's forces . He posted photos and videos of himself on the Internet handling RPGs and other weapons , it said . The Pentagon declined to comment on Harroun 's arrest . However , `` It 's always a concern when terrorist networks in that part of the world and elsewhere seek to recruit Americans , whether they 're in the military or not , '' spokesman George Little told CNN 's Erin Burnett . `` I do n't think this is a widespread phenomenon , and most of our people in this country -- and certainly most men and women in the military -- would not consider joining a terrorist network , '' Little added . Ex-U.S. soldier charged with helping terrorists in Syria . Saudi native charged in New York with fighting for al Qaeda .
Iraq veteran Eric Johnson fought Syria 's government , FBI says . Group he allegedly fought for is part of terrorist group , Justice Department says . FBI arrested Harroun at hotel near Washington .