A 30-year-old Army veteran from Phoenix is charged with conspiring to use a weapon of mass destruction outside the United States after he acknowledged fighting with a designated terrorist group in Syria.

Eric Harroun was discovered after posting videos of him with al-Nusrah Front fighters earlier this year. He met with FBI agents in Virginia after returning to the United States earlier this week, telling them he knew the U.S. designated al-Nusrah a terrorist group but still agreed to be on an "RPG Team," carrying rockets, an AK-47 and anti-armor rockets which were fired at forces loyal to Syrian dictator Bashar al-Assad.

He posted several pictures and videos online showing him carrying rocket propelled grenades and other weapons. The video that vaulted him to national attention came in January, and featured him celebrating in English after a Syrian helicopter appeared to be shot down. He also posted the incident on his Facebook page, writing "Downed a Syrian Helicopter then Looted all Intel and Weapons!"

In another video, he tells Assad "your days are numbered. You are going down in flames. You should just quit now while you can and leave. You're gonna die no matter what. Where you go we will find you and kill you."

He met earlier with FBI agents at a U.S. Consulate in Turkey when he traveled there. He described how al-Nusrah terrorists, who are also part of al-Qaida in Iraq, initially were suspicious of him. Those concerns disappeared after Harroun took part in an attack in which he helped save the life of a wounded comrade. He said he believed he shot 10 people in total, but didn't know how many died.

He also told investigators "that he hated al-Qaeda, that he did not know any al-Qaeda members, and that he would fight against any regime if it imposed Sharia law in Syria because he was opposed to all forms of oppression," an affidavit by FBI Special Agent Paul Higginbotham said.

Harroun also expressed a desire to go to Palestinian territories, writing on Facebook that "The only good Zionist is a dead Zionist."

He served in the U.S. Army from 2000-03, receiving a medical discharge after he was hurt in a car accident.