Extinction Rebellion (XR) has condemned a "fake account" which claimed coronavirus was a "cure" for global warming.
Twitter account XREastMidlands posted images of a sticker reading: "Corona is the cure. Humans are the disease".
The accompanying post said "air and water was clearing" since many went into lockdown.
Extinction Rebellion said the message was "in no way a representation" of its principles and values.
It said: "This account is not managed by Extinction Rebellion UK or Extinction Rebellion East Midlands, and these messages are and so are not the movement.
"We are investigating this now."
Extinction Rebellion Midlands also told the BBC in a statement it was a "fake Twitter account" and the group had requested its removal.
The tweet also drew criticism from Guardian writer and Extinction Rebellion supporter George Monbiot.
He said: "One misanthropic idiot prints out a sheet of paper, sticks it to a pillar and takes a photo.
"Claims to be XR (though XR wants nothing to do with him). Several thousand people: 'you see, all environmentalists are fascists'."