"I think it is a frightening social development," Johan Holmgren, assistant manager at the province of Östra Götaland's Rescue Services department told local radio.
"The common denominator is that such events take place in the socio-economically disadvantaged areas where there are large groups of underprivileged youths turning criminal," he told Swedish Television.
"If you work in this type of area, you have to be mentally prepared for an emergency. You can imagine yourself how it feels to always bear in mind that a stone may fly through the car window anytime while you are on an emergency assignment," Karlsson said.
Ulf Johansson, a regional police chief in Stockholm, regretted the recent development, in that it left public safety personnel vulnerable and exposed.
"You cannot just be punitive. The basic concept is dialogue and cooperation with the good forces among the locals," he told Expressen.
"Reversing the trend in these areas requires first and foremost more police officers. However, it is also a task for the rest of the society to show a positive way out for the socially underprivileged. The last thing to do is to pretend that there are no problems," Ygeman told Expressen.
The scale of last week's tumult was particularly reminiscent of that of May 2013, when violence dramatically escalated in several Stockholm suburbs. The riots began in Husby, when over 100 cars were set on fire. The following day, the riot spread like a wildfire to engulf more areas in Stockholm and also other cities in Sweden. Police efforts associated with those riots cost Sweden's state coffers 10 million krona (roughly 1.2 million dollars), or five times more than a normal week, and 32 police officers were injured.