Three women and a man, accused of recruiting young women for the Islamic State through social media and WhatsApp forums, were sent to prison by a Spanish judge on Thursday. They were allegedly part of a jihadist network that has managed to send 12 women to join the terrorist group in Syria and Iraq.

Spanish National Court Judge Santiago Pedraz "ordered unconditional detention for membership in a terrorist organisation," according to a judicial source.

Police arrested seven suspects this week — four people in Melilla and Ceuta, Spanish territories in northern Africa, a Chilean woman in Barcelona, and two men in the Moroccan town of Castillejos. Two women arrested in Barcelona and Ceuta were apparently about to travel to the Middle East.

The Spanish Interior Ministry believes that "the two men arrested in Morocco were the directors of the network." They were allegedly supported by young female facilitators, who exercised the role of "active recruiters."

Police researchers said that 12 women joined the Islamic State after being subjected to a radicalization process through propaganda on social networks like Facebook. The Moroccan authorities stated that the cell based there determined exactly which volunteers were valid to carry out attacks or marry Islamic State militants.

"This operation against terrorism is very important and we need to be alert all the time," said Spanish Interior Minister Alberto Fernández Díaz during an official trip to Chile. "The Islamic State terrorist organization is a threat for all Western communities and the entire civilization."

Since the Madrid terrorist attacks in March 2004 that left 192 people dead and over 1,500 wounded, Spanish authorities had carried out numerous operations against Islamist terrorism. Many of the jailed people are originally from the Ceuta and Melilla enclaves, which have high Muslim populations that often live under difficult socio-economic conditions.

Apart from the threat of "lone wolf" incidents, such as the recent attack in Sydney, the Spanish authorities are on high alert because members of the Islamic State have threatened several times to retake al Andalus — medieval Muslim Spain.

Another police operation took place in August when two teenage girls from Ceuta and Melilla, aged 14 and 19, were arrested as they allegedly planned to join other women in Morocco, then travel to the Middle East to join the Islamic State.

Gabriel Garroum, a Spanish Middle East researcher and specialist in jihadist movements, told VICE NEWS that the "recruited women tend to be very young girls in complicated family, social and economic environments, who are still building their personalities."

"Not having a clear ideal of life and also the difficult economic situation in Spain makes this type of teenager an easy target for the jihadist recruitment networks," he added.

According to Garroum: "Recruiters play with the message that in a decadent West there are no prospects and no progress for Muslims. However, in the caliphate you will have a better future and a mission in your life."

Many of the women join the Islamic State to become wives of fighters and produce children as part of the group's territorial conquest project. Despite this, Garroum highlights that "the Islamic State is not just looking for combatants but also bureaucrats and technicians ready to run different areas of the caliphate administration."

Bulgarian authorities detained three foreigners wanted in Spain on terrorism charges — who had been on their way to take part in the Syrian war — the country's state security agency said on Tuesday.

The agency stressed that the three suspects — two Moroccans and a Brazilian — were held at the border crossing with Turkey. Interpol issued arrest warrants for these detainees and extradition procedures will be initiated soon.

According to the Spanish Interior Ministry, there are now at least 50 Spanish jihadists fighting in Syria and Iraq. Many of them are descendants from Moroccan migrants or Maghreb people with Spanish residence permissions.

Although most of them are fighting alongside the Islamic State, some combatants have joined Harakat Sham al Islam, an Islamist group based in northern Syria fighting against President Bashar al-Assad's regime.

Designated as a terrorist organization by the US State Department on September 24, this group is mainly formed by Moroccans or descendants of Moroccan migrants. Three Moroccan detainees who were released from the Guantanamo Bay detention camp founded Sham al Islam in August 2013. The group's leader, Ibrahim Bin Shakaran, was apparently killed in a battle with Syrian Government forces in April.