Detectives have been given more time to question two men arrested at Birmingham Airport on suspicion of terrorism offences after flying in from Turkey.
The men - UK nationals aged 40 and 29 - were held as they arrived from Istanbul on Thursday morning.
The 29-year-old was taken to a London police station for questioning on suspicion of belonging to a proscribed organisation under section 11 of the Terrorism Act.
The second man was arrested on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism.
He was taken to hospital for a medical assessment but later transferred to a London police station.
Scotland Yard said on Friday that a warrant of further detention has been granted for both men, which will expire on Wednesday, September 13.