Image caption Cows are allowed to graze on federal wilderness areas if their owners have a permit

A group of stray cows that froze to death in the Colorado mountains must be blown up or set on fire to avoid water contamination, forestry officials say.

The carcasses were discovered near the Conundrum Hot Springs in Aspen by two Air Force Academy cadets in late March.

The cows were found in a ranger cabin where it is thought they wandered during a snowstorm after they were separated from the herd last year.

The plan is to remove the dead animals before they begin to thaw.

US Forest Service spokesman Steve Segin told the BBC: "Obviously, time is of the essence because we don't want them defrosting."

He told the BBC that "negative interactions" with other wildlife were also a concern.

They need to use the minimal tool to get the job done Michael Carroll, Wilderness Society in Colorado

Winter temperatures in the area regularly drop to below 0F (-18C).

The hot springs are inside a federal wilderness area high in the Rocky Mountains, which prevents mechanical options, like chainsaws, from being used.

The options include letting the cows decompose and closing off the area, setting off explosives to break up the animals and speed up the decomposition process, or setting the cabin on fire.

Officials say there are about six cows inside the cabin and several just outside.

Michael Carroll, a spokesman for the Wilderness Society in Colorado, told the Associated Press: "They need to use the minimal tool to get the job done.

"They don't want to leave the land scarred."

According to Mr Segin, the cows' owner has been found through the tags on the animals.

Cows and other animals are allowed to graze on federal wilderness land if the owner has a permit.