Households across Derry have been urged to be on the alert following a spate of oil thefts and attempted break-ins in the city.
Local Councillors and the PSNI have issued separate warnings following a number of incidents over recent days.
A number of thefts have been carried out across the Creggan and Galliagh estates over recent days.
There have also been attempted to steal oil from homes in the Glenowen area of the city.
It is thought that an organised crime gang may be behind the thefts, and that the incidents might be linked.
A spokesman for the PSNI in Derry said: “There have been a number of thefts of heating oil from domestic and business premises over recent days.
In some instances the oil has been taken not through the locked main opening but through a secondary opening,possibly an air valve, at the rear of the tank which can be easily opened.
“If you are able to secure all outlets please do so.”
Sinn Féin Councillor Kevin Campbell warned householders in Creggan and elsewhere to be on the alert for oil thieves .
He made his appeal after five homes along Creggan Heights were targeted within a 24-hour period last week.
Councillor Campbell said: “It’s not uncommon nowadays to hear of heating oil being stolen from homes, but I think it’s unusual for so many to be targeted in one night.
“Having oil stolen is causing severe hardship to many families who cannot afford to refill their tanks.”
He added: “This type of crime takes time and special equipment such as a tanker or large tank in the back of a van and siphoning equipment.
“I would call on people to be observant. If you see suspicious activity in the laneways around a neighbour’s house, particularly if there is no one at home, call the police.”
Colr. Campbell’s part colleague Colly Kelly said the episodes at Glenowen occurred on Wednesday night.
Reports suggest that the would-be thieves were scared off and escaped from the area.
Colr. Kelly said: “I am warning people that this sort of activity is taking place not just in this area but right across the town. Who ever is behind it seems to be going from area to area.
“It is shocking and terrible that local families are being targeted in their own homes like this,” he added.