River 'foam party' prompts Russian investigation
While some social media users referred to the scene jokingly as 'a foam party', others expressed concern about the cause of it and a threat it may pose to nature.
Russia's environment watchdog Rosprirodnadzor said its inspectors were investigating the incident which could have been caused by illegal dumping of chemicals.
The watchdog also said minor traces of an oily substance - possibly used in the production of washing liquid - were found in the river and the samples were taken for further studies.
The local prosecutor's office said it was conducting checks to identify a source of the illegal dumping.
