Image copyright AP Image caption The popular rock formation was fenced off to visitors

Officials at a state park in Oregon are investigating whether a rare rock formation was deliberately toppled.

A mobile phone video appears to show three people pushing against the famed "Pillar Rock" until it collapses.

The unique outcropping, also known as the Duckbill, has long been a popular destination for tourists visiting Cape Kiwanda park on Oregon's Pacific coast.

Officials had at first believed that the coastal sandstone pedestal had naturally eroded.

But they are currently re-evaluating that assessment after being shown the video by David Kalas, a visiting beachgoer.

Image copyright AP Image caption The Duckbill rock after its fall

Mr Kalas said that up to eight people participated in toppling it a week ago, but that five had walked away when the remaining group stayed to push it over.

"We confronted them and they said it was a safety hazard," said Mr Kalas, who had gone there to film a summer holiday video with friends.

"They said one of their friends had broken a leg on it. It's like their weird revenge thing", he added.

Image copyright @meluhnii Image caption Social media users have been posting their tributes to the iconic destination

The pedestal was roughly 10ft (3m) across, and had been a popular destination for tourists seeking photos.

Police and parks officials will meet on Tuesday to discuss possible criminal charges.

A similar incident took place at Goblin Valley State Park in the state of Utah in 2013.

Two Boy Scout leaders received probation and a fine after posting online a video of themselves knocking over a rock formation believed to be about 170 million years old.