At least two people were hospitalized with serious injuries after the incident in the city of Novi Sad.

At least eight people were killed after a concrete roof collapsed above the entrance to a railway station in the northern Serbian city of Novi Sad.

At least two other people were hospitalized Friday with serious injuries, Serbian Interior Minister Ivica Dacic said.

The minister said rescuers were in contact with two people still trapped under the rubble.

“The operation is still ongoing and extremely difficult. More than 80 rescuers are involved, with the help of heavy machinery,” he added.

Ambulances and other emergency teams were dispatched to the city center train station and bulldozers were clearing debris in search of survivors.

Surveillance camera footage showed people entering and exiting the building and sitting on benches on a sunny day before the concrete canopy suddenly collapsed on them.

The station, located in Serbia’s second largest city, reopened in July after three years of renovation work. Construction work continued in parts of the station.

Dacic said the rescue operation was “extremely tough” and would last at least several more hours.

The Blood Transfusion Institute in Novi Sad called on residents to donate blood following the accident.

Serbian Prime Minister Milos Vucevic promised that authorities would investigate the causes of the accident.

“We will insist on finding those responsible, those who should have ensured the safety of the work. My condolences to the families of the deceased,” said the Prime Minister.

“It’s a black Friday for us, for all of Serbia, for Novi Sad,” he added.

Serbian Railways said in a statement that the exterior roof that collapsed was not part of the renovations completed at the station. The accident occurred at 11:50 a.m. local time (10:50 GMT).

“Serbian Railways regrets the accident that occurred, and the causes as well as any new details of the investigation will be announced promptly,” the company wrote in a social media post.

Local media reported that dozens of people may have been injured. The city mayor’s office acknowledged the incident but did not say how many were injured.

News channel N1 said train departures were halted from the station about 70 km (43 miles) northwest of the capital Belgrade.