Iraq has rejected a request from Riyadh to hand over more than 400 Saudi Arabians, whom it has imprisoned on terrorism charges.

According to the London-based newspaper Al-Araby Al-Jadeed, the Saudis were captured along with “hundreds” of other Arabs and Europeans in the fight against Daesh and al-Qaeda.

The paper cited government spokesman Saad al-Hadithi as saying that Baghdad would allow the extradition of those foreigners who have been acquitted of terror charges.

Iraq says all foreign prisoners fall under the jurisdiction of the country’s legal system. So far this year, it has sentenced a German and a Turkish woman to death over their links to Daesh.

Riyadh made the extradition request after pledging $1.5 billion during a donors’ conference held in Kuwait to Iraq’s post-Daesh reconstruction.

Daesh follows the radical ideology of Wahhabism, which dominates Saudi Arabia. It views people of other faiths and creeds as “infidels” punishable by death.

The outfit unleashed its campaign of bloodshed and destruction on Iraq and neighboring Syria in 2014, overrunning large swathes of territory. At the time, extremists from Britain, France and Germany as well as from elsewhere across Europe joined the group to establish a Takfiri caliphate.

As their exodus began, many European leaders ignored repeated warnings that hardened militants could return home one day and hit back, simply because they wanted to see the back of the Syrian government.

On Saturday, the British newspaper The Daily Mail warned that as many as 1,000 Daesh wives were returning to Europe, as the Takfiri caliphate collapses in the Middle East.

European authorities fear the decline of Daesh and its territories is prompting women and their children to flee the Middle East and relocate in the West.

A report by EU border agency Frontex warns the threat is "evolving" and that it is hard to assess the long-term threat of widowed wives and orphaned children.

“An estimated 30 percent of 5,000 foreign terrorist fighters who resided in Europe, and left to Syria, Iraq or Libya have come back to the Continent,” Frontex said.

According to The Daily Mail, European authorities are alarmed by a frightening trend of women having sought "more active roles" in Daesh's campaign.

Several women were involved in a plot to attack Notre Dame cathedral in Paris in September 2016, while there have been numerous high-profile cases of British women fleeing to Syria to marry Daesh terrorists.

Frontex said almost 1,000 women from Europe have joined the different Takfiri groups in the Middle East, mainly Daesh. "Furthermore several hundred minors are also believed to have been brought to, or born in, the same region," it said.

Iraqi officials have announced that the country was holding 500 wives and 1,000 children of Daesh terrorists.

Last July, Iraq famously arrested a 16-year-old German woman, only identified as Linda W., among 26 foreigners in the northern city of Mosul. They turned out to be from the town of Pulsnitz in eastern Germany.