US Army soldiers (illustration)
US Army soldiers (illustration)Yossi Zeliger/Flash 90

A US military reservist was arrested as he tried to travel to fight for Islamic State (ISIS) jihadists, along with a cousin planning to carry out attacks on military installations, authorities said Thursday.

A Justice Department statement said Army National Guard soldier Hasan Edmonds, 22, was detained at Chicago Midway International Airport on Wednesday as he attempted to fly to Egypt, reports AFP.

A cousin, Jonas Edmonds, 29, was arrested at his home in Aurora, Illinois at the same time.

Both had allegedly conspired to wage war on behalf of Islamic State jihadists, with Hasan Edmonds planning to use his military training to join the group on its frontlines in Iraq and Syria.

The Justice Department said Jonas Edmonds planned to use his cousin's military uniforms to carry out an attack on a base in northern Illinois after his relative's departure from the United States.

The pair were captured after unwittingly revealing their plans to an undercover FBI agent, a statement said.

They were arrested on charges of conspiring to provide material support to a foreign terrorist organization and face up to 15 years in prison if convicted.

"We will pursue and prosecute with vigor those who support ISIL and its agenda of ruthless violence," said US Attorney Zachary Fardon, using a common acronym for the Islamic State group.

"Anyone who threatens to harm our citizens and allies, whether abroad or here at home, will face the full force of justice."

The two men face an initial court appearance later Thursday.