Shanghai police have interrogated dozens of people who posted comments online about the deadly New Year's Eve stampede, an officer has told the Sunday Morning Post , in an apparent drive to contain public criticism against the authorities. The questioning came as the municipal government began to negotiate with victims' families about compensation levels, according to a friend of one of the deceased. "The accident caused hundreds of policemen to work extra hours," said the local officer, who asked not to be identified. "It was understood that negative comments or false information online couldn't be entirely eradicated, but the interrogations were deemed as a warning to those unfriendly internet users." The interviews were necessary to contain rumours and maintain social order, the officer added. At least 36 people were killed and 49 injured when pushing broke out among a densely packed crowd on the Shanghai waterfront at 11.35pm on Wednesday. Police have admitted they underestimated the number of people who would show up for the festivities at the Bund, and that they failed to deploy enough manpower for proper crowd control. The officer said some Huangpu district police officers would be sacked and at least one or two city-level officials would be punished over the incident. As part of their effort to manage public opinion, authorities are limiting media access to the victims' families and the injured. Over the past two days, several interviews with relatives by the Post were interrupted by people accompanying them who identified themselves as volunteers at the Shanghai No 1 People's Hospital. They described the interviews as "improper" behaviour that would disturb relatives and affect the hospital's ability to care for patients. The injured are also being treated at two other hospitals. Hundreds of paramilitary officers have been sent to patrol Chen Yi Square, where the stampede broke out, following a protest by several members of victims' families accusing the Shanghai government of negligence. The officers were there as thousands of people went to the square on Friday to lay flowers in honour of the victims. One woman, who said she was a former classmate of Li Xiang, who died in the stampede, said the municipal government had started to negotiate with families about compensation. President Xi Jinping instructed authorities to "do everything in their power" to help those injured and launch an immediate inquiry into the cause of the stampede, according to state media.