The accident happened at around 1 a.m. on the M3 motorway as the group was returning to Poland from a pilgrimage to Medjugorje, a Catholic shrine in Bosnia and Herzegovina.
The bus was carrying 57 passengers and two drivers, all Polish citizens.
According to Hungarian police, the vehicle veered off the road, entered a ditch and overturned.
Preliminary information suggested that the driver may have fallen asleep at the wheel. One of the drivers was detained by Hungarian authorities.
Of the 59 people on board, 12 died and 10 suffered serious injuries and remained hospitalized in Hungary. The other 37 passengers sustained less serious injuries.
Polish authorities have launched an investigation into the crash.
The District Prosecutor's Office in Krosno, southeastern Poland, said investigative work would be carried out at the scene with the participation of a Polish prosecutor.
Poland's Justice Minister and Prosecutor-General Waldemar Żurek said Polish prosecutors were working closely with Hungarian authorities and coordinating their efforts with Polish consular officials.
Prime Minister Donald Tusk said on Sunday that he had ordered a special aircraft to be sent to Hungary carrying foreign ministry officials and medical personnel.
He also spoke with Hungarian Prime Minister Peter Magyar and thanked him for assistance provided by Hungarian emergency services, rescuers and doctors.
Poland's defense ministry said it had prepared additional military transport and medical evacuation capabilities.
A CASA aircraft and a military medical evacuation team were placed on standby in case injured Polish citizens needed to be transported home, the ministry said.
A special aircraft carrying Polish officials and medical specialists, including an anesthesiologist, surgeon, orthopedist and three paramedics, left Warsaw shortly after 8 p.m. on Sunday. They were tasked with assessing the condition of the injured and determining whether they could be safely transported to Poland.
Hospitals in Poland were also placed on standby to admit patients if necessary.
The two bus drivers were questioned by Hungarian police. One was released while the other was detained, according to Polish Deputy Foreign Minister Wojciech Zajączkowski.
He said it was too early to determine responsibility for the crash and that the circumstances would first have to be established by Hungarian investigators.
The identification of the 12 victims was underway, with a Polish consul taking part in the process.
The company that insured the pilgrims said it would cover the cost of bringing the victims' bodies back to Poland.
The Polish embassy in Budapest opened a hotline for relatives seeking information about the accident.
Regional authorities in Poland's southeastern Podkarpackie province, from where the pilgrims traveled, also provided contact numbers for families and arranged psychological support for those affected.
President Karol Nawrocki and senior Polish officials expressed their condolences to the families and loved ones of those who died.
A minute of silence was scheduled for noon on Monday at the Podkarpackie Provincial Office in the regional capital Rzeszów.
The investigation into the cause of the crash was continuing, while Polish and Hungarian authorities remained in contact over the condition of the injured and the identification and repatriation of the victims.
On August 6, 2022, twelve people were killed and 32 others injured when a Polish tour bus carrying pilgrims to Medjugorje veered off a motorway in Croatia and landed in a ditch.
(aj/gs)
Source: IAR/PAP
Click on the audio player above for a report by Piotr Urbaniak