BUDAPEST — A bus carrying Polish tourists overturned on Hungary's M3 motorway in the early hours of Sunday, killing 12 people and injuring dozens more after the driver apparently fell asleep at the wheel. Hungarian police took the driver into custody and said a lapse in alertness was the most likely cause of the crash.

The accident happened around 1 a.m. local time near the town of Mezőkeresztes, roughly 140 kilometers east of Budapest, on the motorway linking the capital with the northeastern city of Nyíregyháza. The bus, a 24-tonne coach, left the eastbound lanes and rolled into a roadside ditch, coming to rest on its side.

Fifty-seven passengers and two drivers were aboard. Firefighters had rescued 35 of those on board when early tallies were issued, with additional passengers still trapped beneath the overturned vehicle. Emergency crews worked to lift the rear axle to reach those pinned underneath before cranes arrived to raise the entire coach.

Hungary's ambulance service reported treating one person with life-threatening injuries, nine with serious injuries and 37 with minor injuries. The toll of 12 dead makes it one of the deadliest road accidents on a Hungarian motorway in recent memory.

Polish Foreign Ministry spokesperson Maciej Wewiór confirmed to Polish news agency PAP that every person aboard was a Polish citizen. The group came from Poland's southeastern Podkarpackie region and was returning home from a religious pilgrimage to Bosnia-Herzegovina when the crash occurred.

Hungary's National Directorate for Disaster Management coordinated the emergency response, deploying firefighters, paramedics and heavy-lifting equipment. The rescue operation was complicated by the weight and position of the bus, requiring cranes to complete the extraction of all passengers.

Hungarian Prime Minister Péter Magyar offered his condolences to the families of those killed and expressed wishes for a full recovery for the injured. Polish President Karol Nawrocki also responded publicly, mourning the loss of Polish citizens in the accident.

The M3 motorway is a primary artery in northeastern Hungary and carries heavy cross-border traffic between Central European countries. Long-distance coach travel between Poland and the Balkans routes frequently through Hungary, with pilgrimages to religious sites in Bosnia-Herzegovina drawing large groups each summer.