An Irish citizen aligned to Islamic State deported from Turkey along with her two-year-old daughter was arrested on her return to Dublin on Sunday on suspicion of terrorist offences, Irish police said.
Ireland expects to repatriate an Irish citizen aligned to the ISIS group and her two-year-old daughter from Turkey this weekend, Prime Minister Leo Varadkar said on Saturday, as authorities in Ankara continues its deportation of detainees.
Smith was not in custody for the four-and-a-half-hour plane journey but Irish police were waiting at Dublin airport for the aircraft's arrival.
Pictures show Ms Smith covered in a pink blanket as she was taken from the plane.
RTE said the child and family agency TUSLA, the Defence Forces and the Gardai are involved.
She is being questioned at a Garda station in south Dublin under section 30 of the Offences Against the State Act.
Nine people killed in South Dakota plane crash
Investigators from the NTSB have been dispatched to the scene in rural Brule County, agency spokesman Knudson said. The three injured were taken to a hospital in Sioux Falls but their conditions was not released.
Smith was a private in the defence forces before transferring to the Air Corps where she served as a flight attendant on a government jet during Bertie Ahern's tenure as taoiseach.
It was reported last month that Smith could be among thousands of ISIS fighters who could go free as the United States looked to move troops out of the region.
She has denied being involved in violence.
"They may be in a position to charge her and if they do, then a prosecution may follow".
When asked whether she was prepared to be prosecuted when she returned to Ireland, Smith said: "Well I know they'd strip me of my passport and stuff and I wouldn't travel and I'd be watched kinda - but prison?"
Earlier this year Ms Smith said she wanted to return to Ireland and described travelling to Syria as her "biggest mistake".
It is understood that a repatriation effort for Smith and her daughter is being assessed. It is believed she is now being detained close to Syria's border with Turkey.