A bus crash in western Bulgaria has killed at least 46 people, including 12 children, authorities said on Tuesday.
The interior ministry said seven people had managed to escape from the burning bus and were being treated in hospital in Sofia for severe burns.
The cause of the crash was not immediately confirmed, but it appeared that the bus hit a motorway guard rail, crashed and then caught fire.
The bus was one of four travelling together. Officials said an investigation would be launched.
Local TV images showed pictures of the charred remains of the vehicle on the Struma motorway, about 45 kilometres west of the capital Sofia, near the village of Bosnek. The scene of the crash has been cordoned off by police.
Bulgaria's interim Prime Minister Stefan Yanev and Interior Minister Boyko Rashkov rushed to the scene on Tuesday morning following the 2am crash.
Mr Yanev called the incident “a huge tragedy" and expressed condolences to the relatives of the victims.
“Let’s hope we learn lessons from this tragic incident and we can prevent such incidents in the future.”
After surveying the damage, Mr Rashkov said "it's a terrifying picture in there".
"I haven't seen anything like that before. Nobody can say for certain how many are there and who they were. The bodies are badly burnt and have to be identified one by one."
He said it would be difficult for officials to determine how many people were in the vehicle because "passengers changed buses during the stops”.
Local media said the North Macedonian and Albanian prime ministers were also on their way.
There are conflicting accounts on the nationality of the victims
Police said the bus driver and an associate were Macedonian, and 50 passengers had Albanian nationality.
But North Macedonian Prime Minister Zoran Zaev appeared to contradict this assessment, saying the majority of victims were Macedonians.
Pictures from the scene showed the bus had North Macedonian plates.
"We don't know if all the victims are from North Macedonia, but we assume so because the bus is registered in the country," Mr Zaev told Nova TV.
Stanimir Stanev, Bulgaria's national police chief, said "of the victims … 12 in total were under the age of 18".
According to bTV, the bus was travelling from Turkey's main city of Istanbul to Skopje in North Macedonia.
Oliver Varhelyi, a European Union Commissioner, sent his condolences to the families and friends of those affected by the crash.
“Terrible news about the tragic bus accident in Bulgaria in early morning hours,” Mr Varhelyi said on Twitter.
“My thoughts and condolences are with the families and friends of those who died as well as with the people and the authorities of North Macedonia.”
In 2019, EU member state Bulgaria had the second-highest road fatality rate in the 27-nation bloc with 89 people killed per million population, according to European Commission data.
Road accidents killed 628 people in 2019 and 463 in 2020 in the country of 6.9 million people, according to official data.
The accidents were often attributed to poor road conditions, outdated cars and speeding.
Two years ago, 17 Bulgarian tourists died when their bus skidded on a wet road and overturned.