Counter-terrorism officers have arrested a man at Gatwick Airport on suspicion of Syria-related offences.
The 24-year-old was detained before boarding a flight, West Midlands Police said.
A woman aged 20 has also been arrested at an address in west London.
The pair are being held at a police station in the West Midlands, while searches are being carried out at two addresses in Birmingham.
A police statement said: "There was no risk to any passengers at Gatwick Airport or to the wider public in relation to these arrests."
Figures published last month showed that there were a total of 280 terrorism-related arrests in 2015 - a drop of 3% compared with the previous year.
The data also revealed that rising numbers of female suspects were being arrested, with 45 held - an increase of 50% compared with 2014.
Since the start of the conflict in Syria, more than 800 people from the UK who are "of national security concern" are thought to have travelled to the region and authorities believe that around half have returned.