Sofia (Bulgaria) (AFP) - Twelve people died and dozens were injured on Tuesday in a mass pileup in thick fog on a motorway in southeastern Bulgaria, whose roads rank as the most dangerous in the EU.

Crashes snared around 50 cars and trucks heading in both directions of the highway linking the capital Sofia to the Black Sea city of Burgas, regional governor Georgi Chalakov told the BTA state news agency.

Images showed overturned and smashed cars and trucks mangled together, as well as burnt-out vehicles, at the scene of the accident near the city of Yambol.

Interior Minister Ivan Demerdzhiev said in a statement that a sudden change in weather conditions was the main reason for the pileup.

Visibility was around 70-80 metres (230-260 feet) immediately before the incident, but dropped to approximately 10 metres within a short period, according to information available to the ministry.

“We are actively working on equipping the toll system gantries with display screens to warn drivers,” he said.

The motorway section should have been closed early Tuesday, Bogdan Milchev, chairman of the Road Safety Institute NGO, told public radio station BNR, blaming the government.

Eleven people died at the scene, while another person died after being admitted to hospital, the health ministry said in a statement.

In total, 51 people were admitted to hospitals in nearby cities, with 13 of them critically injured, it added.

- National mourning -

The government dispatched two aircraft equipped with stretchers and medical teams, as government officials rushed to the scene, while Prime Minister Rumen Radev cancelled his appointments for later Tuesday.

The government wants Wednesday to be a day of national mourning, while President Iliana Iotova, rushing back from abroad, also expressed her condolences.

Bulgaria saw 71 road fatalities per million inhabitants in 2025, the highest rate in the European Union, according to European Commission figures.

Victims blame the Balkan nation’s high number of traffic deaths on reckless driving, poorly maintained roads and an inefficient justice system.

- Stricter penalties -

Romanian Foreign Minister Dan Neculaescu said one Romanian was among the injured and expressed “deepest condolences” to the victims and their families in a post on X.

European Council chief Antonio Costa also said on X he was “deeply saddened to learn of the tragic traffic accident in Bulgaria this morning”.

A total of 456 people were killed in road traffic accidents in Bulgaria in 2025 – down five percent from the previous year and 27 percent lower than in 2019.

In 2019, the EU introduced a target to reduce road deaths and serious injuries by 50 percent by 2030.

A European Commission report in October said that although the EU remains “one of the world’s safest regions for road travel”, the majority of member states were not yet on track to meet the safety target.

The report said that just five of the EU’s 27 countries – including Bulgaria – were on track to meet the target.

In 2023, Bulgaria’s parliament adopted stricter penalties for anyone found to be driving under the influence of drugs.

The cars of accused drivers are now impounded until the trial, even when the suspects have no previous criminal record.

Bulgaria’s busy road traffic due to its position as a gateway to the EU is one of the main factors behind the high accident rate, according to experts.

But Bulgaria’s status as the EU’s poorest member state also plays a role, with around half of the cars registered being more than 20 years old.