Regional Deputy Governor Sergei Tsivilev then got down on his knees to beg forgiveness, and was applauded by the crowd.
President Putin expressed indignation over the disaster – though he did not speak to the crowd.
“People, children came to relax. We are talking about demography and are losing so many people because of what? Because of criminal negligence, sloppiness,” he said.
Russian investigators have so far confirmed the deaths of 64 people, 21 of whom have been identified.
Some of the bodies were badly burned in the Zimnyaya Vishnya (Winter Cherry) complex, and DNA tests will be required, the Investigative Committee says.
It says it is too early to publish the victims’ list, “to avoid any mistakes”.