A man has been arrested on suspicion of a terrorism offence after two military grenades, a gun and chemicals were found at a house in Suffolk.

Officers from Suffolk constabulary made the discovery on Sunday afternoon while executing an arrest warrant at a property in Lowestoft.

A 59-year-old man was initially arrested on Sunday on suspicion of a firearms offence before being further arrested on Monday on suspicion of being concerned in the commission, preparation and instigation of acts of terrorism. The Met’s counter-terrorism command has assumed leadership of the investigation.

More than 60 properties were evacuated after the items were discovered. Police set up a 100-metre cordon around the property shortly before 1pm while an army bomb disposal team, supported by Suffolk fire and rescue crews, made the site safe.

The suspect is being questioned at a Suffolk police station, having been detained at about 12.10pm on Sunday under section 41 of the Terrorism Act, 2000. The Met said the grenades were found to be inert and the gun was believed to be an imitation firearm.

Det Ch Supt Alexis Boon, of counter-terrorism command, said: “After a pre-planned operation by Suffolk constabulary in which officers arrested a man, the Met police counter-terrorism command is now leading this investigation, working closely with police in Suffolk.

“Suffolk constabulary acted quickly to make the area safe, including erecting a cordon around the address as a precautionary measure while enquiries are ongoing. However, we have found nothing to suggest an ongoing threat to the public.”

Police said the cordon was lifted on Sunday evening and only the house where the items were discovered, as well as three other neighbouring properties, remained inaccessible to the public.

They said officers from Suffolk constabulary’s safer neighbourhood teams would remain at the scene over the next few days to provide reassurance to residents.

Chloe Marie Cullen, 23, who had to leave her flat on neighbouring Normanston Drive, told the BBC: “I heard lots of sirens then I saw the police walking up the road towards the house, but I stayed calm as they seemed to have it under control. The police told me to pack an overnight bag as there’s a chance we might not be able to get back in this evening.”

Shaun Waters, the landlord of the Norman Warrior pub in the town, said a number of residents had headed to the pub to seek refuge. “They’ve been told to go to the sports centre for the night, but a lot are waiting to be picked up by family instead,” he told the BBC.

“It was a bit of blitz spirit at first but now people are starting to think about work [on Monday] and not being able to get back to their houses.”