Three British teens who were believed to be on their way to Syria to join militants there were detained in Turkey and quickly returned to the UK and arrested on suspicion of planning terrorist acts, British police Sunday.
The male trio left Britain several days ago, and they were detained in Istanbul after British officials notified Turkish authorities.
The three were arrested on suspicion of the preparation of terrorism acts and were in custody at a central London police station, police said. Their names haven't been released. Two are aged 17 and one is 19.
They are believed to be the latest in a growing number of Britons trying to travel to extremist-held territory inside Syria. Last month, three British schoolgirls left the UK for Turkey and, police believe, crossed the border into Syria to join Islamic State militants.
British legislator Keith Vaz, chairman of the Home Affairs Select Committee, said the latest case shows that the number of young Britons trying to reach the conflict zone in Syria "is on a much larger scale" than had been thought.
Vaz praised Turkish authorities for acting quickly to detain the teens before they entered Syria.
Similar attempts to stop the schoolgirls were unsuccessful — leading some to criticize Turkish officials for not acting quickly enough to keep them from entering Syria.
A senior Turkish government official, who can't be named because of Turkish rules that bar civil servants from speaking to journalists without prior authorization, said the two 17-year-old boys had been detained at Istanbul's Sabiha Gokcen airport Friday by Turkish authorities who were acting on intelligence provided by British officials.
The 19-year-old man was detained at the airport after questioning by police based on profiling at the airport, the official said. All three had flown to Istanbul from Barcelona, Spain.
They were deported to London on Saturday - instead of Spain as is the normal procedure in Turkey - because Britain insisted that they be returned to Britain, the official said.
The teenagers were planning to travel to Syria, the official said. Turkish officials believe they wanted to join IS, but "we cannot say 100 percent that that was the aim," the official said.
The Turkish official described the incident as a "'joint Turkish-British operation," and said Turkey welcomed the timely intelligence and cooperation by Britain.
"Turkey is doing all that it can to stop the passage into Syria, but there has to be cooperation. This operation shows what can be achieved when there is cooperation," the official said.
British counterterrorism officers learned on Friday the teens had gone missing from their homes in Britain and they were thought to be traveling to Syria, police said.
An increasing number of Britons have traveled to Turkey to use it as a crossing point to enter Syria and to join IS extremists who control territory in both Syria and Iraq. The militants have declared an Islamic caliphate in their territory.
British police say roughly 700 Britons have traveled to Syria to join extremists, raising concerns that some may launch attacks inside the UK if they return. Recent cases indicate a growing number of young women traveling there to become "jihadi brides."
Authorities say Internet-based social media have made it much easier for young Britons to communicate with extremists inside Syria.