Two men – one from Birmingham – were arrested on suspicion of terror offences after landing on a flight at Heathrow Airport.
The pair, both aged 21, were detained by detectives from West Midlands Counter Terrorism after their flight from Turkey landed just after 10am on Saturday.
They were being taken to a location in the West Midlands where they were due to be questioned on suspicion of preparing for terrorist acts.
Police said the arrests were intelligence-led and there was no immediate threat to the public. The other man was from Leicester.
