MOSCOW -- Horrifying details emerged from the fire in a Siberian shopping mall. At least 64 people were killed, two thirds of them were children.

In response, thousands of protesters took to the streets demanding answers. Some held pictures of the their dead children. "The truth," they shouted. "We want the truth."

A father broke down recalling the last conversation he had with his daughter.

"I told her to lie down on the floor and breathe. 'Dad,' she said, 'I'm suffocating,'" he said.

Still photo taken from video provided by Russian Emergencies Ministry shows site of fire at shopping mall in Kemerovo, Russia, on March 25, 2018 Russian Emergencies Ministry / Handout / via Reuters

At least 41 children died. It was the beginning of school holidays and the shopping mall was packed. On Tuesday, Russian President Vladimir Putin found himself the target of open hostility.

"Promise me we will know the truth," one woman demanded.

The local deputy governor could only drop to his knees and beg forgiveness.

Closed-circuit TV footage showed the moment the fire broke out, sending a plume of deadly smoke into the hallways. It's still not clear how the fire started, but witnesses say fire alarms failed and doors were locked, trapping those inside.

A man holds a sign reading "A country in fire" during an opposition gathering in tribute to the victims of a Siberian shopping mall fire at Pushkinskaya Square in downtown Moscow on March 27, 2018. AFP PHOTO / Mladen ANTONOV (Photo credit should read MLADEN ANTONOV/AFP/Getty Images) Mladen Antonov / AFP/Getty Images

The protests spilled over to Moscow. Walking through the crowd, you could only hear one thing: silence. It was out of respect, but it also made a statement.

"It shouldn't have happened," said Maria Clarke, a Moscow resident. "Because this is just an amusement center, a shopping center. How is it even possible?"

Putin blamed the fire on criminal negligence. The Russian government seems rattled. At one vigil we attended, the number of security officers far outnumbered the crowd. Wednesday has been declared a day of mourning.