“According to the Quran, Syria is a blessed land, and jihad is obligatory for all Muslims,” she said.

“I always wanted to live under Sharia. In Europe, this will never happen. Besides, my Muslim brothers and sisters over there need help," Khadija, 24, told Al-Monitor over the phone.

In the fall of 2013, her best friend told her that she was planning to join her husband, a jihadist fighter, in Syria. Khadija, who had always wanted to focus on her religion more, became convinced that she should come along. By the end of 2013, the two friends took a flight to Turkey. Contacts there smuggled them across the border into Syria and they were taken to a place near Aleppo . There, they were welcomed by other European women whose husbands were ISIS fighters.

She came across images of black al-Qaeda flags in Syria on the Internet, and she found out that several Dutch Muslims had joined the Islamic State of Iraq and al-Sham (ISIS). They were talking about Sharia, creating an Islamic state and fighting against the Syrian regime, aspects that appealed to her.

AMSTERDAM — Khadija (not her real name) enjoyed a quiet life in the Netherlands, the country she grew up in. She had a place to stay and the opportunity to study.​ However, over the last couple of years, she found it more difficult as a devout Muslim and felt increasing hostility. ​

The London-based International Center for the Study of Radicalization estimated in an April report that up to 2,800 Westerners have gone to Syria to fight, mainly from Europe. Intelligence and security services in Europe say that most of them are affiliated with ISIS and Jabhat al-Nusra, the official al-Qaeda branch in Syria.

"Jihad" attracts women as well as men. Sara, 18, from the Netherlands described how she went to Syria to “follow God’s rules” and to “help the people.” Like Khadija, Sara pointed out that she was not coerced in her decision.

“Muslims do not want to be humiliated in a kuffar [infidel] country where our rights are being violated. I left my country with a big smile, and I don’t care that the [Dutch] government doesn’t want me back," she wrote on her Facebook page.

Sara radicalized after she became friends with Salafist Muslims in the Netherlands. She began to cover herself with an Islamic face veil. That resulted in insults on the streets, even from Muslims, many of whom consider the full black veil an extremist form of Islam.

Montasser AlDe'emeh, a researcher studying jihadist fighters at the universities of Antwerp and Leuven in Belgium, believes there are various reasons why European women join radical Islamist groups. The rise of right-wing parties — often anti-Muslim — in Europe is one factor, as is the women's difficult childhood.

“These girls feel there is no place for them in society, as they are being rejected by everyone, including Muslims. By contacting Muslims who feel the same way, they try to fulfill needs ​such as love, recognition and sisterhood,” he told Al-Monitor.

AlDe'emeh, a Palestinian Muslim, said that creating a caliphate by connecting all the Islamic countries is the ultimate goal of European jihadists who join ISIS.

“The fighters believe that the fall of the Ottoman Empire led to dictatorial regimes in the Muslim world. They do not believe in the colonial borders that were determined by the British and the French,” he said.

According to Khadija, most European jihadist women went to Syria with their husbands. Others get married on the spot, just like Sara, who recently married a Belgian fighter called Brian de Mulder.

A week after she arrived, Khadija was introduced to a Tunisian ISIS fighter. “A religious man with green eyes, I really liked him,” she said. After she agreed, a local sheikh performed the marriage.

European female jihadists in Syria describe a sober, domestic life, in which their duties of jihad play a key role. The main task of the female jihadist is supporting her husband, who fights, and being a good Muslim. This is part of the "inner or greater jihad," which is much needed in Syria, because, according to these extremists, the West does not care about the war-torn country. Fighting is considered to be part of the "outer or smaller jihad."

“I baked cookies, cooked for my husband, chatted with women and played with my pets. I had five fish, two birds and four cats,” Khadija said, smiling nostalgically, adding that she did not have contact with the locals, except for one Syrian woman, while in Syria.

ISIS, which has spread across Raqqa, northern Aleppo and some of the border areas, attracts young jihadists from all over the world. The European fighters in Syria form a tight community. On social media, male fighters share updates about attacks that their comrades have carried out, pictures of fallen jihadists and videos about their missions. As for the female jihadists, Quran verses are being shared and pictures of meals and snacks — next to that a Kalashnikov — appear on Facebook. Western countries are often being criticized and fighters who die as martyrs are hardly being mourned, because it is believed they go straight to​ heaven.

A European jihadist from Raqqa said she “pities Muslims who still live in a kuffar country."

“Here we feel that Allah is with us. Brothers and sisters are happy. Allah’s flag is waving in every street. So sweet," she wrote on Facebook.

But local Raqqa residents bemoan ISIS’ occupation of their city and the imposition of strict Islamic rules. Women are forced to wear a niqab and smoking is prohibited. Not a day goes by without an execution, crucifixion or torture. According to a local activist, the numbers of foreign jihadists are still increasing.

“Fighters from the United States, Czech Republic, Belgium, Germany, Norway, the Arab world. Believe me, I have seen them all, living in big houses and hotels. Of course, they have plenty of food,” Ammar Mohammed (not his real name) told Al-Monitor via Skype.

ISIS is not only involved in a battle with the Syrian regime, but also with their rival Jabhat al-Nusra. On May 27, a car bomb exploded in front of a hotel in Raqqa where the children and wives of foreign fighters live. ISIS said dozens of women, children and fighters were wounded and accusations were directed at Jabhat al-Nusra.

In Europe, there are growing concerns that European radicals will parlay their experiences in Syria into terrorism back home. These fears were realized when it became clear that the French national suspected of having shot dead three people in the Jewish Museum in Brussels last month spent most of 2013 fighting with radical Islamist groups in Syria.

Khadija also returned to the Netherlands after a two-month stay in Syria. Her husband brought her to the border himself after she told him she missed her family. She now lives in Amsterdam again, but her radical sentiments remain strong.

“I would like to go back to Syria soon," she concluded. “If I die over there, I die on God's path."