At least 45 people, including 12 children, died on Tuesday after a bus carrying tourists crashed and caught fire on a highway in Bulgaria, Reuters reported.

Seven people were injured after they jumped from the burning bus. They were taken to a hospital in Bulgaria’s capital city of Sofia.

“We have an enormous tragedy here,” said Bulgarian interim Prime Minister Stefan Yanev, according to Reuters. Interior Minister Boyko Rashkov said that the scene of the accident was terrifying. “I have never seen anything like that before,” he said.

While the reason behind the accident is unclear, an unidentified official said that the bus could have hit a highway barrier either before or after it caught fire.

“Human mistake by the driver or a technical malfunction are the two initial versions for the accident,” said Bulgarian Investigative Service chief Borislav Sarafov.

Most of the tourists in the bus were North Macedonians, The Guardian reported. The country’s foreign minister Bujar Osmani said that the bus was returning to Skopje city after a holiday in Turkey.

In 2019, Bulgaria had the second-highest number of road fatalities among the 27 countries that comprise the European Union, AP reported, citing data from European Commission.