A 21-year-old man from Birmingham has been arrested on suspicion of attending what police said on Saturday was a Syrian terrorist training camp.
The man was detained by officers under terrorism laws on Friday when he arrived at Gatwick Airport on a flight from Istanbul.
West Midlands Police said they questioned the man at a police station before releasing him on bail as their enquiries continued.
In a statement, officers said the case was not connected to the case of two 21-year-old men who were arrested at Heathrow airport by counter-terrorism officers on Monday when they flew back to Britain from Istanbul.
Police said on Saturday the pair had been charged with traveling to Syria to engage in terrorism.