A mountain biker who worked for the US Forest Service has been killed by a grizzly bear near a Montana national park.

A newlywed bride has admitted killing her husband of eight days by pushing him from a cliff in a US national park while they argued over her second thoughts about the marriage.

They were newlyweds, but she was having second thoughts about the eight-day-old marriage, court documents say. The couple drove the short distance from their Kalispell home to Glacier National Park, where they argued. He grabbed her by the arm, but she pulled away and shoved him face-first off a cliff to his death.

A man aiming to start hoax rumours of a Bigfoot sighting in the US was run over and killed as he stood in the road trying to startle drivers.