Updated

Police say two people are dead and 20 are injured following multiple crashes involving about 50 vehicles on a foggy stretch of Interstate 77 in southwestern Virginia.

Virginia State Police spokeswoman Corinne Geller said dozens of troopers and emergency workers were working to clear vehicles from the interstate. She says some were stacked on top of one another and tractor-trailers jackknifed or turned on their sides. At least half of the vehicles involved were commercial.

Geller says heavy fog reduced visibility to zero.

There were several crashes Tuesday morning on the southbound lanes, and in the afternoon, an accident in the northbound lane involved at least two tractor-trailers and shut down traffic in that direction.

Detours were set up.