Bulgarian police have made four arrests after 18 people, including a child, were found dead in an abandoned truck in Bulgaria, its government says.
The truck appeared to have been illegally transporting a group of migrants.
Thirty-four people, including five children, were rushed to hospitals and some were in a critical condition, the health minister said.
The people in the truck were cold, wet and had not eaten in days, he said.
It is believed to be the deadliest incident involving migrants in Bulgaria.
Bulgaria has long struggled to deal with large numbers of people trying to enter the European Union from Turkey.
The truck – found near the village of Lokorsko, 12 miles (20km) north-east of Bulgaria’s capital, Sofia – was illegally transporting the migrants in hidden compartments in which they had suffocated, police said.
Health Minister Asen Medzhidiev described the conditions inside the truck: “There has been a lack of oxygen to those who were locked in this truck. They were freezing, wet, they have not eaten for several days.”
Police believe those discovered were from Afghanistan and were being illegally smuggled to Serbia.
One of the four people arrested had already been sentenced for human trafficking, Atanas Ilkov, a senior police official, .
Bulgaria has faced accusations it is abusing people attempting to enter from Turkey, with asylum seekers saying they have been blocked, arrested, stripped and beaten.