Roman Podbrezova, 65, had gone for a morning walk when he saw the drastic change to the river which runs through the centre of the town.
‘I just could not believe my eyes,’ he said. ‘The river was dark red. It was like something from a horror film. Blood cascading through the centre of town.’
Another local said: ‘This is really creepy. Yesterday evening I walked past here and it was its normal color.
‘Now it looks like someone slaughtered 1,000 virgins or something. I'm not superstitious, and we've never had any serial killers or anything like that here, but this isn't normal.
Police spokesman Elena Antalova said: ‘We are checking the source of the blood and what caused it.