There'll be an increase of armed officers on the streets in Bedfordshire, Cambridgeshire and Hertfordshire in the run up to Christmas.
Officers are reminding people to be vigilant and report any suspicious activity.
Footfall into town centres is expected to increase over the festive period, and shoppers and party-goers are being urged to stay alert when out and about.
Detective Superintendent Glen Channer, from the Eastern Region Special Operations Unit and Counter Terrorism Policing, said: “We know that the Christmas period is a busy time, with many more people than usual visiting town centres, enjoying the night-time economy, and attending events such as Christmas markets.
“We want everyone to have a safe festive period and that’s why we’re urging people stay alert and make it harder for terrorists to carry out or plan an attack.”
It's part of a new operation which will see armed officers carry out more visible and proactive patrols.
The move, which has not been introduced because of any specific intelligence, is designed to help make the public feel reassured and ensure more regular armed patrols are carried out at key locations across the three counties.
Chief Inspector Julia Hands, of the Bedfordshire, Cambridgeshire and Hertfordshire Armed Policing Unit, said: “The safety of the public is our number one priority which is why we’ve decided to increase the visibility of our armed officers. From this week onwards our armed officers will be more visible at key sites across the three counties, carrying out proactive patrols and talking to the public.
“I’d like to reassure the public that this move is not being taken because of any intelligence about any current threats, and if anyone does have any concerns please do speak to one of our officers while they’re out and about.”