Authorities in Kazakhstan say that an operation to extract Kazakh citizens from Syria last week led to several arrests.

The May 7-9 operation returned 231 Kazakhstanis, Deputy Foreign Minister Yerzhan Ashikbayev told a joint press conference with the National Security Committee, or KNB, on May 13. The total includes 16 men, 59 women and 156 children, mostly under age 7. Ashikbayev added that 18 of the children had lost their parents.

On their return, all 16 men and four of the women were detained on suspicion of joining the Islamic State group. The KNB has not provided details about the suspects, except that they hail from different regions of Kazakhstan, including major cities. The rest of the women have been placed for a month in a special reintegration center near the city of Aktau in western Kazakhstan. They are being investigated for involvement in terrorism as well, Ashikbayev said.

Though the numbers are impossible to verify, by some counts several thousand people from the former Soviet Union traveled to the Middle East to join ISIS since 2013. Some brought their families; others had children there.

The United States and the Syrian Democratic Forces aided the evacuation, the Foreign Ministry said.

In January, 47 Kazakhstanis, including 30 children, were returned from Syria. Two evacuated men were later jailed for eight years for terrorist activity.

Leader of the Nation Nursultan Nazarbayev, commenting at the time, claimed that "Kazakhstan always supports its citizens, regardless of their location."

Amanzhol Urazbayev, a reserve KNB colonel who frequently comments on security matters, told Eurasianet that Kazakhstans mission is not only humanitarian.

Also important is that the evacuation allows Kazakhstan to neutralize the threat imposed by terrorists before they return home on their own, said Urazbayev.

Since the militant groups defeat on the ground in Iraq and Syria, security experts have feared these radicals could return and spread havoc. In 2014, ISIS released a propaganda video featuring Kazakh-speaking children calling for the slaughter of infidels. After an attack on foreign tourists last year, Tajik authorities blamed a group of young men who had pledged fealty to ISIS, though they had not traveled to the Middle East.

Earlier this month Tajikistan brought home a planeload of children from Iraq, where their mothers are imprisoned on ISIS-related charges.

According to the Foreign Ministry, more than 200 citizens of Kazakhstan, mostly children, remain in Syria.