BERLIN (Reuters) - A German teenager being held in an Iraqi jail after running off to join Islamic State is being investigated on suspicion of membership in a foreign terrorist organisation, German prosecutors said on Monday.

Federal prosecutors are investigating the case of 16-year-old Linda Wenzel alongside those of three other women in Iraqi detention, of whom at least one had German citizenship, they said.

If they bring charges, prosecutors can seek the extradition of Wenzel, who has said she will cooperate with German authorities.

Foreign ministry spokeswoman Maria Adebahr said consular officials had confirmed the citizenship of the first two women during a meeting last Thursday and were due to meet the two others on Monday.

Wenzel, who was detained by Iraqi security forces last week when they recaptured Mosul, told German media at the weekend that she regretted joining the jihadist group and wanted to come home to her family.

She fled her home in the city of Pulsnitz last year shortly after converting to Islam. Prosecutors lost track of her after she left Istanbul on her way to the war zone.

German media said Wenzel, who has been seen by German consular officials, had a gunshot wound on her left thigh and an injury on her right knee that she said was caused during a helicopter attack.