PM says situation on the River Odra was caused naturally

The Polish prime minister has said the environmental disaster on the River Odra that resulted in the death of thousands of fish was an act of nature.

Despite extensive testing, scientist have been unable to find, so far, significant evidence of toxic substances that may have been introduced to the river.

"It is becoming increasingly clear that the situation on the River Odra was a natural event; there were no large discharges of chemical substances, neither mercury nor other substances that were used to scare us," Mateusz Morawiecki said on Thursday.

The head of government also said that "all specialists and hydrologists know perfectly well that talking about fish poisoning by mercury - was a verbal abuse and a very significant misunderstanding".

"We can see that the Odra is recovering quickly, nature is regenerating quickly," he added. "Those apocalyptic visions can now be put aside."

He said that the government "will do everything to restore the natural ecosystem to its original state as soon as possible".