Image copyright Colorado Department of Transportation

A section of highway in the US state of Colorado has been totally destroyed by two boulders "the size of a building", officials say.

The road was hit by a slide "consisting of dirt, rock and two huge boulders", the Colorado Department of Transportation said.

Photos posted on its Facebook page show a trench 8ft deep (2.5m) left by the boulders.

The road between the towns of Cortez and Telluride is closed indefinitely.

The heavier boulder is estimated to weigh almost 4,000 tonnes and measured 50ft (15m) in height and width.

Image copyright Colorado Department of Transportation

Work is under way to clear loose rock to prevent further slides, the department says.

The two boulders will have to be drilled and blasted. In it is not yet known when the road will reopen.