A police cordon is expected to remain in place for the rest of the week as investigations into unidentified chemicals continue.
Suffolk Police first imposed a 100m cordon around Normanshurst Close on Sunday afternoon after a search uncovered military grenades, a firearm and the chemicals following a pre-planned warrant.
Dozens of homes, including some on Fir Lane, were initially evacuated before the cordon was reduced shortly before midnight. The terraced property being searched, as well as three neighbouring homes, remain cordoned off, with residents unable to return to their homes.
Officers from Suffolk Police remain at the scene, and are expected to continue to do so to provide reassurance to the public.
A spokesperson for East Suffolk Council said: "The people who remain evacuated from their homes at Normanshurst Close have been offered emergency accommodation. However, at this time, they have made alternative arrangements.
"The offer of support remains in place for as long as they are unable to return to their homes and so, should their circumstances change, we will be available to offer assistance."
The Met Police Counter Terrorism Command began leading the investigation into the "suspicious items" following the arrest of a 59-year-old man, named locally as Clinton Hicks.
Mr Hicks was initially arrested at the scene on suspicion of possessing a firearm. He has since been further arrested on suspicion of being concerned in the commission, preparation and instigation of acts of terrorism, a spokesperson for the Met Police confirmed.
He has been detained and is currently in police custody in Suffolk.
Usually, police are required to charge or release suspects within 24 hours, although people suspected of terrorism can be detained for 14 days without charge.
The grenades were assessed and found to be inert and the firearm believed to be an imitation, while Counter Terrorism officers were called to assist the recovery of a quantity of chemicals.
Neighbours said Mr Hicks had "around 15 cats", was often seen feeding the seagulls and one neighbour said he had converted to Islam and made weekly trips to a mosque in Norwich.
Following the search, detective chief superintendent Alexis Boon, of the Met Police Counter Terrorism Command, said there was nothing to suggest an ongoing threat to the public.
As well as Army Explosive Ordnance Disposal officers and Suffolk Fire and Rescue crews, charity volunteers were called to the scene, with 15 Salvation Army volunteers on-hand to serve refreshments to the emergency workers.
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