More and more women are being drawn to join the campaign of the Islamic State of Iraq and Greater Syria (ISIS) mainly through social media sites as the militant group continues to expand into the Middle East.

Initially, ISIS actively opposed women from joining and claimed that they did not belong in combat. Social media campaigns targeted at women were strictly limited to fund raising and urging them to send their men to fight.

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But as the group gains momentum and comes closer to establishing a caliphate, recruitment guidelines were gradually adjusted to allow for exceptions.

Women play key roles in a state, said Shiraz Maher, a terrorism analyst from the International Center for the Study of Radicalization.

Now, women are being actively recruited through social media primarily for their supportive roles with promises of a committed jihadist husband, a home in the Islamic State and the chance to live their lives dedicated to their God.

While the actual statistics of women who have joined ISIS remain unknown, the International Center for the Study of Radicalization say at least 30 European women have traveled to Iraq and Syria, either to accompany their jihadist males, or with the intent to marry ISIS fighters, Time reported.

In a separate RT news agency report, some 60 women signed up with the Al-Khansaa security force, an all-women arm of the ISIS based in Raqqa, Syria.

In recent months, two Australians and two British girls reportedly traveled to Syria to marry militant fighters. Two Somalian teens and at least one Canadian have also been known to have joined the extremist group in Syria.

American Shannon Maureen Conley, 19, was detained by authorities as she prepared to board a flight to Turkey on the way to Syria. She was charged with conspiring to aid an international terrorist group.

Although female recruitment strategies are less intense than for the males, observers note it is more than enough. Women can easily search the web and build a community with like-minded women.

Umm Layth, a Syrian-based Western blogger with a huge social media following, writes on her Tumblr that opposition from family is the hardest part in joining the ISIS. British police suspect Layth is actually Aqsa Mahmood, 20. She was reported missing by her family late last year.

Al-Khanssa, a female blogger in Syria, offers interested female recruits on what items to bring and not to bring to the Middle East. Her website also details religious instructions sourced from Islamic sites and verses from the Koran.

"The main role of the muhajirah (female migrant) here is to support her husband and his jihad and (God willing) to increase this ummah (Islamic community)," al-Khanssa writes.

TagsISIS, ISIS recruitment of women, International Center for the Study of Radicalization, Al-Khansaa, Shannon Maureen Conley, Umm Layth, Al-Khanssa