Dyfed-Powys Police will be stopping suspicious vehicles
Farmers in Powys are being called on to be extra vigilant following a sharp increase in sheep theft in the county.
Nearly 1,000 sheep have been stolen from Powys farms during 28 sheep rustling raids since April 2010.
Dyfed Powys Police revealed that more than 320 sheep were taken in separate thefts from three farms in the Knighton area.
And more than 200 sheep were stolen from two farms in the Builth Wells area.
Dyfed Powys Police will now be stopping suspicious vehicles in rural areas.
They are calling on farmers and other members of rural communities to be vigilant and report any suspicious vehicles or anyone acting suspiciously to the police.
NFU's Brecon and Radnor county chairman, Gwyn Price, said: "These large-scale thefts cannot be done using a family car, so the criminals must be using livestock vehicles.
"The criminals have targeted hotspots such as Knighton and Builth Wells, so I would say they must have some knowledge of the area.
"In this sort of crime electronic tagging of sheep doesn't help catch the thieves because the tags can be cut out and replaced with other tags."
Although most of the 967 sheep stolen since April 2010 have been taken from Radnorshire, thefts have also taken place in the Llanfyllin area
NFU Cymru's Montgomeryshire county chairman, Edward Chapman, said that current market prices meant that the theft of 40 sheep would cost a farmer £2,000 and the theft of 40 lambs more than £3,000.
"It is deeply worrying for livestock farmers that this type of activity is on the increase and is starting to form an upward trend," he added.
"We now have a significant number of sheep thefts that have occurred throughout the county and it is unlikely that Montgomeryshire is alone in facing this problem.
"Anyone who sees anything suspicious should take down any relevant information such as vehicle registration numbers and report the incident immediately to the police."
Dyfed-Powys Police Communities and Partnerships Sergeant Kelvin Briggs said: "These are serious offences which can have a significant impact on the livelihood of the victims and the rural community at large.
"Police officers will be stepping up patrols in rural areas across Powys and making vehicle stops in a bid to provide reassurance to members of the farming community.
"Officers are also urging people who see any suspiciously activity in the area to call police as all matters will be fully investigated."
Dyfed-Powys Police can be contacted on 101 (if in Wales) or the independent Crimestoppers charity on 0800 555 111.