Grizzly bear mauls cyclist to death in US National Park

A grizzly bear has mauled a mountain biker to death in a national park in the US.

The attack took place a mile away from a campground in the western part of the Glacier National Park in Montana.

The victim has been named by Montana authorities as US Forest Officer Brad Treat, 38.

He was cycling in the Half Moon Lakes area of the Flathead National Forest with an unnamed friend when they apparently surprised the bear.

According to Flathead County Sheriff Chuck Curry, Mr Treat was ripped from his saddle by the bear while his uninjured friend rode off to find help.

His body was found an hour after emergency services were called and was declared dead at the scene.

The area has been closed to the public which is around 3 miles from the park's west entrance.

Armed officers are searching for the bear responsible but have yet to find it.

Before this incident there have only been 10 bear-related human deaths in Glacier Park since 1910.

Glacier officials say there are usually one or two non-lethal encounters between bears and humans each year inside the park.

Grizzlies in have been designated a threatened species in the US since the 1970s, but their numbers are increasing and so are encounters between humans and bears.