Kansas-born Allison Fluke-Ekren, 42, admitted to engaging in "terrorism-related activities" in Syria, Libya, and Iraq between 2011 and 2019.

"Fluke-Ekren ultimately served as the leader and organizer of an ISIS military battalion, known as the Khatiba Nusaybah, where she trained women on the use of automatic firing AK-47 assault rifles, grenades, and suicide belts," the department said.

"Over 100 women and young girls, including as young as 10 or 11-years-old, received military training from Fluke-Ekren in Syria on behalf of ISIS (Islamic State)."

Her husband was a member of the extremist Ansar al-Sharia group which attacked the US mission in Benghazi, Libya in 2012, and then became a leader of an Islamic State sniper group in Syria.

The department said the two were involved in extremist activities across the Middle East after they left the United States in 2011.

While in Syria, the department said, she spoke of desires to bomb a US shopping mall or university.

In 2016-17 she became leader of the all-woman Khatiba Nusaybah battalion, which undertook physical, medical and weapons training to support Islamic state.

Fluke-Ekren was apprehended in Syria sometime after the early-2019 territorial defeat of Islamic State, and flown to the United States on January 28.

The court record indicates that her attorneys and the Justice Department spent months negotiating her guilty plea on a single count, supporting a foreign terrorist organization, a charge which brings up to 20 years in prison.

She is scheduled to be sentenced on October 25.