Three men from Birmingham have been arrested by counter-terrorism police after arriving on a flight from Oman.
They were detained at Heathrow Airport on suspicion of possessing articles and documents with intent to use them for terrorist purposes overseas.
Officers held two men, aged 33 and 39, from Small Heath and another, aged 33, from Alum Rock, all in Birmingham.
The pre-planned and intelligence-led arrests were made by officers from the West Midlands counter-terrorism unit.
West Midlands Police said the arrests were not in response to any immediate threat to public safety.
The men were held under Section 57 of the Terrorism Act 2000.