A man is in police custody after the bomb squad had to be called to a block of flats over a suspicious package.
Sussex Police were sent to Belmont Close in Hassocks, West Sussex, at around 9.30am on Saturday, where they discovered a device.
People living in the Middlewick House block of flats, as well as those in a handful of properties nearby, were told to temporarily evacuate for safety reasons.
Bomb disposal teams were called to the scene to carry out a controlled explosion, with a cordon in place on Belmont Close.
Residents were allowed to return to their homes on Saturday evening after the area was made safe.
Detective Superintendent Carwyn Hughes said: "I would like to thank the residents for their patience while we made the area safe."
A 50-year-old man is in custody after being arrested on suspicion of making an explosive substance.