Iraqi forces have detained a group of female Islamic State fighters in Mosul, five of whom are reportedly German. Berlin is investigating whether one of them is a 16-year-old girl who left the country a year ago to join the terrorist group.

Iraqi troops captured a group of some 20 female fighters last week in the city of Mosul, which was held by Islamic State (IS, formerly known as ISIS/ISIL), Die Welt reported.

It added that at least five of them were German citizens, while others came from Russia, Turkey, Canada, Syria, Libya and the Caucasus.

1. German ISIS girl Linda W. (16 y/o) was apparently captured in Mosul by Iraqi security forces: https://t.co/mkrbo0yfV1pic.twitter.com/AcmqQtVSrF — Björn Stritzel (@bjoernstritzel) July 17, 2017

The women were hiding in tunnels built by the terrorists, media reported, adding that Iraqi forces allegedly found weapons and suicide vests during the arrests.

A 16-year-old student from the German federal state of Saxony, Linda W., is presumably among the five German women, Die Welt newspaper reported, citing security sources. The authorities are investigating whether the teen held in Mosul was Linda, Lorenz Haase, chief prosecutor for the state of Saxony, said.

She reportedly converted to Islam and falsified documents to travel alone to Istanbul, Turkey, and then on to Syria back in the summer of 2016.

Linda’s parents reported that she was missing immediately after her disappearance. The authorities issued an international search warrant for the student in July 2016. The General Prosecutor's Office in Dresden, Saxony, began an investigation into the girl for alleged preparations of violent acts against Germany. The probe was suspended due to the absence of the main suspect, DW earlier reported.

“There are new details in the case of Linda W., which are being examined at the moment,” a spokeswoman from Saxony’s State Criminal Police Office (LKA) told Die Welt on Monday.

According to the LKA, Linda was in contact with IS supporters while in Germany and allegedly got in touch with the terrorist group online, DW reported.

Vian Dakhil, a Yazidi member of the Council of Representatives of Iraq, confirmed the identity of the girl on Twitter, releasing pictures during her alleged capture by Iraqi forces. Linda was an IS sniper, Dakhil claimed, adding that her mother “didn’t deny” that the girl in the photos was Linda.

The mother of the #sniper girl was found in #Germany and she didn't deny that she is her daughter @dw_arabic@dw_globalpic.twitter.com/liZRXbgy8N — Vian Dakhil (@VianDakhil) July 17, 2017

READ MORE: Germany must expect attacks by lone wolves & terrorist groups at ‘any time’ – intel chief

Some 930 people left Germany to fight in Syria or Iraq, 20 percent of whom were women, Hans-Georg Maassen, the president of Federal Office for the Protection of the Constitution (BfV), the German domestic security agency, said earlier in July.

A BfV report, also released in July this year, states that young people can easily be indoctrinated to “develop a readiness to consequently obey the order to kill unbelievers.”

The report warns that Germany is the focus of Islamist terrorism and “terrorist incidents are possible in Germany at any time in the future.” The Islamist following in Germany in 2016 amounted to approximately 24,400 individuals, the document added.