The relatives of Shamima Begum, who joined the Islamic State group in Syria at the age of 15, say they plan to challenge the move to strip her of her U.K citizenship.
Her family’s lawyer, Tasnime Akunjee, says the young woman’s relatives are considering “all legal avenues” to contest the decision.
Government sources are reported as saying it is possible to strip the 19-year-old’s citizenship.
Ms. Begum, who left east London in 2015, and has said she wanted to return home.
She told ITV News it was “kind of heart-breaking to read” of the home office’s decision, adding that it was “unjust for both she and her son.
In an interview she said she was sorry ISIS was responsible for the deaths of so many people.
Ms. Begum was found in a Syrian refugee camp last week after reportedly leaving the last stronghold of ISIS.