Impressionable teenage girls and young women are increasingly running away from their homes and leaving distraught parents in Germany to join the "Islamic State" (IS) in Iraq and Syria.

IS has already overrun large parts of those two countries, claiming them as part of their new caliphate where the militants impose a strict version of Islamic law.

IS propaganda targeting women doesn't use major platforms, according to Florian Endres, an expert on radicalization at Germany's Federal Office for Migration and Refugees (BAMF).

"They use smaller groups and forums where they try to reach Western girls and women, trying to persuade them to become a part of this new elite community, this new Islamic state," he told DW, adding that IS is building a new state and to do so needs women to start families.

Persuading "sisters" in Europe

Girls who already are part of the Salafist scene in Germany are active on social media networks, which is where they spread information, Enders said. Initial contact goes both ways, he added, sometimes a person seeks out information about how to move to Syria or Iraq and sometimes girls are approached by women who have already made the journey and joined IS. "They report live on how great life is there," Endres said.

A German woman who calls herself "Muhajira," which means emigrant, has been blogging and posting on Facebook and Twitter since she left Germany in 2013. She has written about her life in Iraq "on the foundation of jihad, on the foundation of honor." In one of her early posts, she exalted how after leaving Germany she was finally "free to wear my niqab as I like without seeing and hearing ridicule."

The blogger offers recipes as well as promises of whatever information would-be jihadist wives from Germany might need. She is also open to helping find girls for fighters "because there are a lot of unmarried mujahedeen here."

"These women romanticize life there, but you have to remember, Syria is in the midst of a civil war," said Endres of the BAMF.

Glamorizing life behind the veil

There are many tweets and blogs that appear to have been written by Western women married to militants active in IS and building a new Islamic society. The young women gush about the joys of family life and raising children to be new fighters for Islam.

In Europe, girls turn to Twitter and ask.fm, a question-and-answer platform, about how to get to Syria or Iraq. An issue often raised is how to deal with desperate parents who refuse to let their daughters leave home to join the jihad. Obtaining parental permission can be a major obstacle for minors who need parental approval to travel or marry.

The BAMF, Endres said, tries to help parents prevent their daughters from radicalizing and leaving home, but it's a difficult prospect. The young people know next to nothing about politics and religion, which makes them highly approachable, Endres said.

"But there is one thing the young people are really good at, and that's social media," he said, adding that children's conspiratorial behavior on the Internet makes control difficult for parents.

Almost 40 percent of the girls and women estimated to have left Germany to join extremist groups are under the age of 25, and some are still minors, according to Germany's domestic intelligence agency. About 650 male German Islamists have made their way to join the militants in Syria and Iraq, and more than 100 young women.