The two detainees were picked up by the Syrian Democratic Forces, a US-backed ground force that has been fighting IS across parts of northern and eastern Syria.

"Two US citizens, charged in separate cases with federal violations, have been transferred from the custody of the Syrian Democratic Forces to US custody and transported to the US where they will soon appear in federal courts," US Department of Justice spokesman Wyn Hornbuckle said Tuesday.

Defendant Ibraheem Izzy Musaibli, 28, of Dearborn, Michigan is due to be arraigned in federal court in Detroit on Wednesday on charges of helping IS from April 2015 to June 2018.

"The indictment alleges that, for a substantial period of time, defendant Musaibli provided material support to ISIS, one of the most violent terrorist organizations in the world," US Attorney Matthew Schneider said in a statement.

"We will vigorously prosecute anyone who provides, or even attempts to provide, support to terrorists."

It was not immediately known if Musaibli had an attorney.

Samantha Elhassani, meanwhile, has been charged in Indiana with making false statements to the FBI. She is due in court for an initial hearing at an unconfirmed date.

The Justice Department said Elhassani was accompanied by her four minor children, all US citizens now in the custody of the Indiana Department of Child Services.

"Indiana DCS will make any necessary determinations regarding their custody, safety and well-being," it said.

Elhassani's son appeared in IS propaganda videos and her husband was an IS sniper before he was killed in a drone strike, according to reports.

Commander Sean Robertson, a Pentagon spokesman, said the Defense Department provided aircraft and aircrew to fly the detainees from Syria to the United States.

US officials have previously said the SDF have captured hundreds of IS fighters, many of them from other countries that have little or no interest in allowing them home.