Police have closed the Trakia motorway in the Sofia-bound direction after a serious pile-up in Yambol region, Burgas regional police said.
Drivers heading from Burgas to Sofia must use a detour via Karnobat and Petolachkata.
Many vehicles are involved in the crash. It happened in an area covered by Yambol regional police, where there is fog.
Police did not say how long the motorway will stay closed.