Police have searched two homes in the Easton area of Bristol
Police are continuing to search the home of a 19-year-old man arrested in Bristol under the Terrorism Act.
The man, from the Easton area, is being held as part of an investigation into Andrew Ibrahim, 19, who was charged under the Terrorism Act in April.
Officers have concluded the search of a second nearby property and discounted it from their inquiries.
Mr Ibrahim, of Westbury-on-Trym, Bristol, has been remanded in custody on charges of plotting terrorism acts.
Avon and Somerset Police said no armed officers were involved in the latest arrest, and that no evacuations or controlled explosions were needed.
'Appeal for calm'
In an attempt to reassure local residents, extras patrols have been introduced and hundreds of letters delivered to homes.
Assistant Chief Constable Jackie Roberts said a meeting between police and community leaders had been "extremely important and very positive".
"We are very grateful for the support we have received from the local communities," she said.
"I would reiterate what was said at that meeting, and appeal for calm.
"I appreciate that when people hear about arrests under the Terrorism Act, they will be concerned."
She added: "Everything we have done has been with public safety remaining our paramount priority and that continues to be our primary objective."
Police have been scrutinising CCTV footage since Mr Ibrahim's arrest.
They say they have been "painstakingly" working their way through thousands of days worth of images and looking at more than 2,000 exhibits and more than 2,500 documents.