Eleven people died in a traffic accident involving dozens of vehicles on both sides of a foggy stretch of highway in eastern Bulgaria on Tuesday, Prime Minister Rumen Radev said. Police, firefighters and ambulance crews rushed to the scene on the A1 road that links the capital Sofia with the eastern city of Burgas. Images on local media showed cars and trucks piled up across six lanes of highway, many crushed, overturned, or veered off to the side. 50 injured people were transported to hospital, according to the interior ministry. Radev described the accident as a "tragedy" in a statement during a visit to Bulgaria by European Commission President Ursula von der Leyen. He said that he had deployed aircraft to evacuate the wounded and planned to visit the scene. Read: 11 killed, 33 injured as bus collides with truck near Punjab's Pakpattan Von der Leyen said she would cut her visit short. "I would like to express my deepest condolences and I would like to pay respects to the rescue teams," von der Leyen said. Briefing reporters at the site of the accident, General Secretary of the Interior Ministry, Lyubomir Nikolov, said that fog was the likely cause of the accident which started with a collision between a bus and a truck on the side of the highway heading towards Burgas. Chief Inspector Todor Mishinev from the Yambol Regional Directorate of the Ministry of Internal Affairs told Nova TV that some people were still trapped in their cars. "Right now, the priority is rescue operations. Once they are completed, the procedural and investigative actions will be carried out," he said.