TERROR arrests in South Yorkshire this week will mean extra armed and unarmed police on patrol, the force has said.
Men aged 22, 36 and 41 were arrested in Sheffield on Tuesday along with a 31-year-old from Chesterfield.
Detectives were granted extra time to question them on suspicion of being involved in planning acts of terrorism on Wednesday night.
Assistant Chief Con David Hartley, of South Yorkshire Police, said: “The arrests were intelligence led and pre-planned as part of an ongoing investigation by Counter Terrorism Policing North East and MI5, which we are continuing to support.
“In light of the activity, and as planned throughout the festive period, you will see an increased visibility of both unarmed and armed patrols right across the county.
“Please be reassured that this is for your safety, to provide support and deterrence ahead of what is likely to be a busy couple of weeks.
“We have a detailed understanding of all our events, shows, sporting fixtures, markets, attractions and seasonally busy places, and it’s in these places that you will see armed and unarmed staff.”
Residents reported hearing what sounded like explosions when the arrests were made. Counter Terrorism Policing North East said this was part of the method of entry.
A spokesman added: “Residents will be kept as informed as possible and we are grateful for their understanding, patience and support while these enquiries continue.”
Supt Una Jennings, based in Sheffield, said: “I want to offer my reassurance that we will continue to serve and protect the public of South Yorkshire.
“We work very closely with our colleagues at the North East Counter Terrorism Unit and we will ensure we maintain these strong links in order to provide a high level of service and delivery to everyone in our community. Public safety is our utmost concern.”
Report terrorism concerns on 0800 789 321 or dial 999 in an emergency.