Turkey says a foreign intelligence operative suspected of helping three British schoolgirls join the Islamic State extremist group has been detained.

Foreign Minister Mehmet Cavusoglu said the suspect acted even though he or she worked for the intelligence agency of a country that is part of the U.S.-led anti-IS coalition. Cavusoglu did not identify the country but said it was not the United States or a member of the European Union.

Cavusoglu, who was interviewed on A Haber TV, said he had shared the information with his British counterpart.

The three teenage girls traveled to Turkey last month, from where they are believed to have crossed into Syria.

Their journey highlighted the difficulty of halting the radicalization of young Muslims.

Britain's Foreign Office had no immediate comment.