"Our windows were open as it was warm outside, and I heard a huge rumble and saw a plume of dust; that's all I saw,” an 86-year-old woman named Vera, who lives about 200 yards away, told the Associated Press. “Later, I heard what happened." 

Earlier in the afternoon, rescuers freed two women who had been trapped under the rubble. They were in critical condition, said Vesna Turkulov, the head of the Vojvodina medical center where they were taken.

The search and rescue operation was complicated by the sheer weight of the concrete and was expected to continue through the night, said Luka Causic, who heads the interior ministry's Center for Emergency Management.

Interior Minister Ivica Dacic told Serbia’s Tanjug news agency earlier he did not expect the death toll to rise significantly. Five of those killed have not yet been identified, said Serbian President Aleksandar Vucic, promising justice.

"It is difficult to say anything meaningful," Vucic said in a televised address. "As the president of Serbia, I demand that all those who are responsible for this are ... punished."

As the night fell, hundreds of people lit and laid candles outside the Novi Sad city hall to honor the victims of the disaster, some of them in tears.

"What's there to say? I have worked at that railroad, I know it. This is terrible," said Dragan Vujicic, a 70-year-old pensioner.

Train departures from the station have been halted, according to the N1 news channel. The channel reported that a building reconstruction had been completed this summer but that the part of the roof that collapsed had not been included in the project.

"This is a black Friday for all of Serbia and Novi Sad," Prime Minister Milos Vucevic told reporters. "Regardless of the fact that this building was constructed in 1964, we will insist that those responsible for this tragedy are identified."