Ex-National Guardsman accused of plotting attack in support of Islamic State
A member of Ussud Al-Anbar (Anbar Lions), a group affiliated to the Islamic State of Iraq and the Levant (AFP)

A former member of the Army National Guard has been charged with trying to aid Islamic State militants by buying weapons for an attack on U.S. soil, authorities said on Tuesday.

The suspect, Mohamed Bailor Jalloh, 26, of Sterling, Virginia, was arrested by Federal Bureau of Investigation agents on Sunday, the Justice Department said in a statement.

The previous day, Jalloh had bought and test-fired a 5.56mm Stag Arms assault rifle at a Virginia gun store. The weapon was rendered inoperable before he left the dealership with it, the statement said.

Jalloh had told an FBI informant in May that the best time for an attack was during the Muslim holy month of Ramadan, which ends on Tuesday, it said.

U.S. Magistrate Judge John Anderson ordered Jalloh held pending a July 12 detention hearing in Alexandria, Virginia, a court document showed.

Jalloh, who was born in the West African nation of Sierra Leone, faces federal charges of attempting to provide material support and resources to a designated foreign terrorist organization. If convicted, he faces up to 20 years in prison.

Jalloh's lawyer, Ashraf Nubani, who has a long record of defending suspects accused of ties with radical groups, could not be reached for comment.

An affidavit said that a now-dead member of Islamic State in March had brokered Jalloh's introduction to an FBI informant. The Islamic State member was plotting an attack in the United States and thought it would be carried out by the informant and Jalloh, it said.

Jalloh met the informant in April and May. He praised the gunman who killed five U.S. service personnel in Chattanooga, Tennessee, in July 2015.

Jalloh said he had been thinking about an attack similar to that carried out by former Army Major Nidal Hassan, who killed 13 people at Fort Hood, Texas, in 2009, the affidavit said.

He gave $500 to someone that he believed was a member of Islamic State but was in fact an undercover FBI employee, the statement said.

Jalloh told the informant that he had quit the National Guard in Virginia after listening to online lectures by U.S.-born al Qaeda preacher Anwar al Awlaki, who was killed in Yemen in a U.S. drone strike.

(Reporting by Ian Simpson; Editing by Tom Brown)