Eric Harroun, 30, of Phoenix, Ariz., was accused of using a rocket-propelled grenade while fighting with the al-Nusrah Front, an alias of al Qaeda in Iraq, according to a statement issued on Thursday by the U.S. Attorney’s Office in the Eastern District of Virginia.

“Harroun, a U.S. citizen who served with the U. S. Army from 2000 to 2003, was charged by criminal complaint with conspiring to use a destructive device outside of the United States, which carries a maximum penalty of life in prison, if convicted,” the statement said.

“According to an affidavit filed in support of the criminal complaint, Harroun allegedly crossed into Syria in January 2013 and fought with members of the al-Nusrah Front against the Bashar al-Assad regime in Syria,” it added. “The affidavit alleges that Harroun was trained to use an RPG by members of the terrorist organization and that he fired an RPG and posted online multiple photographs of himself carrying or posing with RPGs and other military weapons.”