Neighbours living near properties in Batley and Sheffield spoke of their shock after the raids on Wednesday morning.
Four people were arrested - a 55-year-old woman and a 44-year-old man from Batley on suspicion of an offence under Section 15 of the Terrorism Act – terrorist fundraising; and two men from Sheffield, aged 40 and 36, on suspicion of an offence under Section 5 of the Terrorism Act – preparation to commit an act of terrorism.
North East Counter Terrorism Unit said the man and woman from Batley, and the 36-year-old from Sheffield were bailed pending further enquiries on Tuesday evening.
The 40-year-old man from Sheffield remains in custody.
The group had been taken to a Police Station in West Yorkshire for questioning.
As part of the investigation, five properties in Sheffield, Batley and Dewsbury are being searched. All five searches have now concluded, the Unit said.
The investigation is Syria related.
Det Chief Superintendent Clive Wain, head of the North East Counter Terrorism Unit, said yesterday: “We understand that people may be concerned following today’s arrests however we would like to reassure communities that today’s activity is as a result of an ongoing investigation which is intelligence led. There is no evidence to suggest that communities are at risk.
“If you have any concerns as a result of the activity then please contact local police via 101.
“If you suspect that there may be suspicious activity in your area, or are concerned about someone’s behaviour, then contact the confidential Anti-Terrorist Hotline on 0800 789 321 and a specialist officer will assist you.”
Neighbours in Sheffield yesterday described their shock at being woken during a dawn raid on their neighbour’s red-brick council home.
One neighbour, who didn’t wish to be named, said: “It’s scary to think it could happen so close to you.
“We were woken up this morning by banging. I thought it was just a van door slamming but then we heard men shouting.
“As soon as we heard the shouting we looked out the window and saw the police everywhere and then just drew the curtains as we didn’t want to get involved.
“I don’t know much about him [the man who lives there] to be honest, but I do see him go out in his van.”
Another neighbour, who also wanted to remain anonymous, said: “My grandson heard lots of banging at around 6am this morning and when he looked outside there was a load of police cars around the street, but apart from that we haven’t heard anything.
Ernest Balderson, who lives on the same street, said the man was a “smashing neighbour” from a “nice, lovely family”.
Mr Balderson said: “He’s a nice chap and he would always help out clearing the snow and would kick up a fuss if he saw me gardening or decorating.”
Two police officers stood sentry on the quiet and secluded street, while forensics teams continued to search the property.
Splintered panels on the doors indicated where police teams had managed to break their way through earlier this morning.
In the back garden children’s toys sat on the grass, while a pile of nappies had gathered outside the back door.
Neighbour Kathryn Smith, who has lived in the area for 35 years, said: “There have been a few dodgy people living in that house in the past, but I would never say that about him. He is so open and inviting and is not one to keep himself to himself.
“He is really big part of the street and the community and nobody I know has anything bad to say about him.”
In Batley, two of the people arrested were described as “nice and normal” by their next door neighbour.
Jane Smith was woken up at 6am by a loud bang coming from the back of her property and saw “about 30” police officers entering the back of her neighbours’ house.
The neighbour said she saw police photographing parts of next door’s garden and realised that her neighbours had been arrested.
Ms Smith, 46, said: “I’ve only been living here a month but I knew them quite well - as well as you can know someone in that time. “The woman told me she was from Ireland and her name was Mary but she’d converted to Islam when she married her husband.
“She told me her converted name was Miriam and she said she’d met her husband in Turkey.”
The property, on Burnsall Road, Batley, sits along a row of newly built houses owned by housing provider Home Group and is in a quiet neighbourhood.
Ms Smith, a grandmother with four children, spoke fondly of her next door neighbours and their three children.
“They seemed lovely - the kids even brought food round for us at Eid.
“They have three children - two girls and a boy between 11 and 15 I think - and their car is still outside the house now.
“Normally it’s gone at about half past 7 when they take their kids to school.”
Describing the police presence, Ms Smith said she had been surprised to see so many.
She said: “They came in about three or four cars and have been in and out of the house all day.
“Two unmarked police cars are still here now.
“I didn’t speak much to husband - I think he was a white van driver and I know he worked nights - but the wife was really nice and normal.
“I know that they had been complaining that they had not had their Internet connected but I didn’t think anything of it.
“I’m really surprised - you just don’t expect it, do you?”
The housing group which owns the Batley homes released a statement confirming the arrests.
Bhavna Patel, Home Group customer services manager for Yorkshire, said: “We can confirm that 3 Burnsall Road, Batley is a Home Group property.
“We also confirm that a police raid took place this morning at the address during which a 55-year-old woman and a 44-year old-man, who had been living there since August 2015, were arrested.
“The tenants were vetted and checked by us as part of a tenancy application process and we found no reason to decline their application. The address is one of 55,000 homes that we own, housing more than 120,000 people a year in across 200 local authority areas in England, Scotland and Wales.”