Two men have been arrested at Heathrow Airport on suspicion of terrorism offences.
The men, aged 21 and from Leicester and Birmingham, were detained just after 10:00 BST having arrived on a flight from Turkey, West Midlands Police said.
They were later taken to the West Midlands for questioning on suspicion of preparing for terrorist acts.
The arrests were intelligence-led and there is no immediate threat to the public, the force said.
It said West Midlands Counter Terrorism detectives arrested the men.
The two men have since been released on bail.