Three British teenagers suspected of trying to travel to Syria were released on bail late Sunday after being questioned for 24 hours on suspicion of preparing acts of terrorism, police said, according to AFP.
Two 17-year-old boys from northwest London and a man aged 19 were detained by authorities in Turkey on Friday and were deported to Britain on Saturday, where they were promptly arrested by counter-terrorism officers.
"They have been bailed to return to a central London police station pending further enquiries," a spokesman for London's Metropolitan Police announced late Sunday.
Scotland Yard police headquarters in London said earlier that counter-terror officers were told Friday that the 17-year-olds had "gone missing and were believed to be travelling to Syria".
"Officers alerted the Turkish authorities who were able to intercept all three males, preventing travel to Syria," a spokesman said, according to AFP.
A Turkish official confirmed that the three were detained by security forces in Istanbul on Friday and were deported back to Britain on Saturday.
The 17-year-olds were detained upon information provided by Britain, the official told AFP.
Meanwhile the 19-year-old, identified as MAA, was detected by Turkish airport police who scrutinized the passengers arriving in Istanbul on a flight from Barcelona, the official said.
The official said that according to initial data, the teenagers were headed to Syria -- most probably to join the Islamic State (ISIS) group.
The Scotland Yard spokesman said the three had been returned to Britain and were arrested "on suspicion of the preparation of terrorist acts", contrary to the Terrorism Act 2006.
"All three have been taken to a central London police station, where they remain in custody."
The Turkish official praised the cooperation with the British authorities, saying, "This shows we can get results when serious co-operation, including timely intelligence, is in place."
The incident comes just weeks after an international police hunt was launched to find three east London schoolgirls who travelled to Istanbul on their journey to Syria.
However, Shamima Begum, 15, Amira Abase, also 15, and Kadiza Sultana, 16, are now feared to have reached the conflict zone and are believed to be staying at a house in the city of Raqqa, a stronghold of ISIS.
Turkey, which has been accused by its Western allies of failing to do enough to stop jihadists crossing into Syria from its territory, had accused Britain of failing to provide information about the girls sooner.
An estimated 550 Western women have travelled to join extremists in Iraq and Syria -- while more than 500 people are believed to have left Britain to fight with IS, often travelling via neighboring Turkey.
Keith Vaz, who chairs parliament's home affairs scrutiny committee, said Britain needed to prevent people travelling to Syria in the first place.
"We need to be vigilant. Clearly this flight of young people to Turkey in order to go to Syria is on a much larger scale than we envisaged," he added.