Eight so-called Islamic State suspects, one of which is British, have been deported from Turkey back to their home countries.
Turkey's Interior Ministry said seven Germans and one Briton were deported, but it did not identify the suspects.
The Home Office in London also refused to disclose any details, including whether the suspect had arrived back in the UK, saying it did not comment on individual cases.
However, a 26-year-old man has been arrested by police on suspicion of Syria-related terror offences as he arrived at Heathrow Airport from Turkey today.
Scotland Yard said he was held "on suspicion of preparation of terrorist acts under section 5 of the Terrorism Act 2006".
Turkey has declared its determination to deport alleged foreign IS members who are held in its prisons or in parts of Syria it controls.
That came after Ankara was condemned by some western governments for sending forces to parts of north east Syria to drive out Kurdish fighters it considers to be terrorists even though they were allies in the US-led push to defeat IS in the region.
Turkey has already deported a US national and IS suspect who was stuck in a no man's land between Turkey and Greece after Athens refused him entry.
Ankara said the United States had agreed to take him back.
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