Some 10 people were killed in the accident and seven others injured on Sunday when the minibus overturned in southern Bulgaria, the country’s interior ministry said in a statement.
Police said while the migrants did not carry any identification documents, survivors of the accident told authorities they were Pakistani and Afghan nationals.
The minibus smuggling the migrants into Europe was reportedly driven by a 16-year-old Bulgarian who had no driver’s license. He died in the crash along with nine migrants. According to the interior ministry, the 16-year-old had a criminal record.
Bulgarian television channel bTV reported that the teen driver likely fell asleep behind the wheel, but the interior ministry statement would not speculate on cause of the crash, because it was still under investigation.
The accident happened on a highway near Pazardjik, close to the Greek and Turkish borders.
European Union-member Bulgaria has become a main entry point for migrants traveling to western and northern Europe through the Balkan route.
The number of people illegally crossing its southeastern border with Turkey has been reduced after the construction a razor-wire-topped barrier.
In May, Bulgarian authorities estimated that some 3 000 people had illigally entered the country so far this year. Another 3 000 migrants remain stranded in Bulgaria’s refugee shelters, according to the latest available official data.
The Wall Street Journal reported in 2015 that on the Bulgarian side, smugglers cram migrants in buses and minivans and drive them eastwards to Sofia, the capital.
At night, smugglers drop off their human cargo at parking lots of big shopping malls on the outskirts of town from where they continue by car or a different minivan. Many stay over in the center of Sofia, where they wait, often for days, for the next step of their journey.
At night, gangs moved up to 500 migrants nightly across the Timok river into Serbia and then onto Hungary. Police said migrants pay as much as $1 000 per person to be transported from Hungary to Germany.