South African security authorities say a teenager was taken off an airline flight because the 15-year-old girl was suspected to be leaving her home in Cape Town to join the Islamic State group.

State Security spokesman Brian Dube said in a statement Monday that the girl has been returned to her family's care. He said authorities questioned the girl and debriefed her family.

Dube said the State Security department was investigating how the teenager had paid for the flight and how she may have been recruited.

South Africa's State Security Minister David Mahlobo said in local media that the girl's social media accounts showed she was interested in joining the Islamic extremist group.