Armed officers have begun patrolling gas installations in the UK amid heightened security alerts.
The officers are guarding several facilities
The Ministry of Defence (MoD) is guarding gas facilities near Peterhead and Garlogie in Aberdeenshire.
MoD police have also been deployed to patrol Bacton gas terminal in Norfolk and Easington in East Yorkshire.
The officers are equipped with firearms and are authorised to shoot to kill. The Home Office said it was not in response to any particular threat.
The MoD police have been drafted in to guard what is deemed "critical infrastructure" as part of a major review of the UK's security strategy.
The officers are working 12-hour shifts and are patrolling the installations. Seven officers have been stationed at St Fergus, five at Garlogie and six each at Bacton and Easington.
They are working in conjunction with the facilities' normal security.
An MoD spokesman said cars containing armed officers would be driving around the Bacton site.
The MoD has not confirmed whether other officers would be on patrol at the Grangemouth refinery in Stirlingshire.
Supt Dennis Jackson , speaking outside the St Fergus facility, said: "The threat is enduring as far as terrorism internationally is concerned and clearly at this time the government has chosen to explore tactical options available to support operations up and down the country.
"We have got to look from the international perspective that infrastructure in other countries has been the subject of attack and given the climate we live in at the moment these steps are advisable."
He said the officers would be based at the facility until March.
A Home Office spokeswoman said: "We will continue to monitor the risk from terrorism and we keep our response under constant review."