Bulgarian police discovered an abandoned truck on Friday containing the bodies of 18 migrants, who appeared to have died of suffocation.
The Interior Ministry said that according to initial information, the truck was carrying about 40 migrants and the survivors were taken to nearby hospitals for emergency treatment.
Bulgarian Health Minister Assen Medzhidiev said most of the survivors were in very poor condition.
“They have suffered from lack of oxygen, their clothes are wet, they are freezing and obviously they haven't eaten for days,” Medzhidiev said.
The truck was found abandoned on a highway near the capital, Sofia. The driver was not there, but the police discovered the passengers in a secret compartment under a load of wood.
Authorities did not immediately release the nationalities of the migrants. Bulgarian media reported that they were all from Afghanistan.
Bulgaria, a Balkan country of 7 million people and the poorest member of the European Union, is on a major route for migrants from the Middle East and Afghanistan seeking to enter Europe from Turkey. Very few plan to stay, and most use Bulgaria as a transit corridor on their way west.
Bulgaria has erected a barbed wire fence along its 259-kilometre (161-mile) border with Turkey, but with the help of local people smugglers, many migrants still manage to get inside.
In Great Britain, in October 2019, police found the bodies of 39 people inside a refrigerated container that had been transported to England. British police said all the victims, whose ages ranged from 15 to 44, came from impoverished villages in Vietnam and it was believed that they had paid smugglers to take them on a perilous journey to a better life abroad.
Police said they died from a combination of lack of oxygen and overheating in an enclosed space. The truck discovered in the town of Grays, east London, had arrived in England on a ferry from Zeebrugge in Belgium.