Detectives have released two of the three men arrested after two bombs were found in a flat near Gatwick Airport in West Sussex.
Police evacuated the area
The men, aged 41, 38 and 35, were being held under the Terrorism Act following the discovery of two "home-made" devices in Langley Green, Crawley, on Tuesday.
Sussex Police said a third man remained in police custody on Friday morning for further questioning.
The force was granted an extra 72 hours to question the men during a special hearing at Crawley Magistrates Court on Thursday.
Police say the suspects are of western European origin.
Army bomb disposal experts were called to the property on Tuesday - they found two bombs.
People living near the flat were moved out of their homes overnight as a precaution.
The arrests were made under the Terrorism Act 2000.
'Too early to speculate'
Inspector Geoff Sharnock said: "They are effectively home-made bombs.
"Three men have been arrested. One was arrested elsewhere and two were arrested at the flat."
Detective Chief Inspector Tony O'Donnell said: "At this stage the search of the address is continuing and it's too early to speculate on the motive behind this incident.
"It has not, at this stage, been linked to any target or specific organisation."
Under the Terrorism Act 2000, suspects can be questioned for up to a week without charge, with the permission of magistrates.