A man who travelled to Syria to fight with an al-Qaeda affiliate has been charged over alleged plans to carry out a terror attack on the US military.
Abdirahman Sheik Mohamud, 23, allegedly gained training with al-Nusra Front and was instructed by a radical cleric to carry out an attack in the US.
He is accused of telling another man he wanted to kill American soldiers “execution-style” at a military base.
He faces charges of material support of terrorism and making false statements.
“Identifying and neutralising the threat posed by foreign terrorist fighters who return to the United States is one of the National Security Division’s highest priorities,” Assistant Attorney General John Carlin said in a statement.
It is the latest example of US officials bringing charges against those allegedly helping Islamic State (IS) and other militant groups.
Mr Mohamud, from Ohio, left the US in April 2014 shortly after becoming a naturalised citizen, travelling to Syria after a flight to Istanbul, according to prosecutors.
His brother, Aden, had been killed while fighting with the group in Syria.
Mr Mohamud allegedly told two unnamed people when he returned to the US in June 2014 he wanted to attack a military base or prison, killing three or four people “execution style”.
He told one person he had received weapons, explosives and hand-to-hand combat training, and the other he had gone through physical fitness and guarded a camp at night, according to the indictment.
He sent videos of himself in Syria to an unnamed person. In one video, he pointed to a gun in a holster on his hip and in another, he stood in front of a white house with a black flag on it.
Mr Mohamud was initially arrested in February in Columbus by local law enforcement and transferred into federal custody on Thursday after charges were brought by a grand jury.