According to the health minister, 34 survivors, including five children, were taken to hospitals and some were in critical condition.
At least 18 people were found dead in an abandoned truck near the capital Sofia in Bulgaria, officials said.
The truck was transporting timber and carrying refugees and migrants hidden in a compartment, the country’s interior ministry said in a statement on Friday.
Health Minister Asen Medzhidiev said 34 survivors, including five children, have been taken to hospitals in Sofia and some are in critical but stable condition.
“Those who were locked in that truck lacked oxygen. They were frozen, wet, they hadn’t eaten for several days,” Medzhidiev told reporters.
The truck was found abandoned along a highway near the capital Sofia.
The driver wasn’t there, but police discovered the passengers in a secret compartment under a load of wood.
Authorities did not immediately reveal the nationalities of those found.
According to the Interior Ministry, the police were looking for the escaped drivers of the truck.
Bulgaria lies on a route used by refugees and migrants from the Middle East and Afghanistan to enter the European Union.
Most do not stay in the country, instead trying to move on to richer countries in Western Europe, often via smuggling networks.
In 2015, three Bulgarian truck drivers were arrested and later charged with the deaths of 71 migrants found dead alongside an Austrian motorway.
In October 2019, British police found the bodies of 39 people in a refrigerated container that had been transported to England. Police said all of the victims, aged 15 to 44, were from impoverished villages in Vietnam and are said to have paid smugglers to take them on a risky journey to a better life abroad.
Police said they died from a combination of lack of oxygen and overheating in an enclosed space. The lorry, spotted in the town of Grays, east of London, had arrived in England on a ferry from Zeebrugge in Belgium.